( 4 ) average daily and year-end europe brent crude spot price as reported by the u.s. energy information administration . ( 5 ) average daily and year-end henry hub natural gas spot price as reported by the u.s. energy information administration . the prices for both wti and brent crude oil showed improvement during 2017 and continued to strengthen through most of 2018 ; however , they decreased significantly during the last quarter of 2018. in 2019 , crude-oil prices improved during the first few months , and became more stable during the second half of the year . the end result was the average price for crude oil in 2019 was approximately 10 % lower than the average price for 2018. in general , activities associated with the exploration of oil and gas in the u.s. onshore market are more sensitive to changes in the crude-oil commodity prices , as opposed to larger international and offshore projects which take multiple years to plan and develop , and once announced and started , will continue through completion , despite changes in the current price of crude oil . the improvement in crude-oil prices in 2017 and 17 most of 2018 led to elevated levels in u.s. onshore activities associated with both the exploration and production of crude oil . additionally , during this time period , public announcements of investments in larger international and offshore projects were elevated and activity levels began to improve in 2018 and continued to improve into 2019. however , the continued vola tility and lower level of crude- oil prices in the last quarter of 2018 and during 2019 did negatively impact the activity levels in the u.s. onshore market which decreased in 2019. information published by the u.s. energy information administration ( “ eia ” ) , shows that the inventory of wells drilled but uncompleted ( a “ duc ” well ) was 6,566 as of december 31 , 2017 , increasing to a peak in february 2019 at approximately 8,500 , and ending 2019 at 7,573. this data indicates that during the period of higher activity in 2018 , operators were drilling wells but not completing them as the duc inventory grew . however , as activity levels began to fall in late 2018 and into 2019 , and operators began to drill fewer new wells , they were also completing some of the wells that had been previously drilled , which is reflected in the lower duc inventory at december 2019. in north america , the land-based rig count increased 45 % during 2017 and another 19 % during 2018 , which had a positive impact for both services and product sales to this market over this time period . the build in levels of activities on development projects and producing fields in the u.s. unconventional reservoirs during 2017 continued to strengthen during most of 2018 , until october 2018 when the commodity price weakened significantly and activity levels decreased . the lower commodity prices in 2019 led to a 10 % decrease in the annual average land-based rig count and a decline in u.s. based activities in 2019. outside of north america , activities associated with the exploration for and production of oil dropped to current lower levels during the industry downturn which began at the end of 2014. although activities have not yet increased , we believe these markets have shown signs of recovery for 2020 and beyond as our clients have announced new capital investment projects throughout 2017 , 2018 and 2019. results of operations operating results for the year ended december 31 , 2019 compared to the years ended december 31 , 2018 and 2017 we evaluate our operating results by analyzing revenue , operating income and operating income margin ( defined as operating income divided by total revenue ) . since we have a relatively fixed cost structure , decreases in revenue generally translate into lower operating income results . results for the years ended december 31 , 2019 , 2018 and 2017 are summarized in the following chart : 18 results of operations as a percentage of applicable revenue for the years ended december 31 , 2019 , 2018 and 2017 are as follows ( in thousands , except for per share information ) : 2019 / 2018 2018 / 2017 revenue : 2019 2018 2017 % change services $ 474,193 71.0 % $ 486,820 69.5 % $ 480,264 74.1 % ( 2.6 ) % 1.4 % product sales 194,017 29.0 % 214,026 30.5 % 167,555 25.9 % ( 9.3 ) % 27.7 % total revenue 668,210 100.0 % 700,846 100.0 % 647,819 100.0 % ( 4.7 ) % 8.2 % operating expenses : cost of services * ( 1 ) 345,641 72.9 % 343,833 70.6 % 333,365 69.4 % 0.5 % 3.1 % cost of product sales * ( 1 ) 149,938 77.3 % 153,131 71.5 % 131,593 78.5 % ( 2.1 ) % 16.4 % total cost of services and product sales 495,579 74.2 % 496,964 70.9 % 464,958 71.8 % ( 0.3 ) % 6.9 % general and administrative expenses ( 1 ) 48,023 7.2 % 62,910 9.0 % 47,737 7.4 % ( 23.7 ) % 31.8 % depreciation and amortization 22,605 3.4 % 23,087 3.3 % 24,524 3.8 % ( 2.1 ) % ( 5.9 ) % other ( income ) expense , net 5,319 0.8 % ( 737 ) ( 0.1 ) % 632 0.1 % nm nm operating income 96,684 14.5 % 118,622 16.9 % 109,968 17.0 % ( 18.5 ) % 7.9 % interest expense 14,690 2.2 % 13,328 1.9 % 10,734 1.7 % 10.2 % 24.2 % income before income tax expense 81,994 12.3 % 105,294 15.0 % 99,234 15.3 % ( 22.1 ) % 6.1 % income tax expense ( benefit ) ( 12,290 ) ( 1.8 ) % 25,447 3.6 % 18,249 2.8 % nm 39.4 % income from continuing operations 94,284 14.1 % story_separator_special_tag our ability to continue these initiatives depends on , among other things , market conditions and our ability to generate free cash flow . our ability to maintain and increase our operating income and cash flows is largely dependent upon continued investing activities . we are a netherlands holding company and substantially all of our operations are conducted through subsidiaries . consequently , our cash flow depends upon the ability of our subsidiaries to pay cash dividends or otherwise distribute or advance funds to us . we believe our future cash flows from operating activities , supplemented by our borrowing capacity under existing facilities and our ability to issue additional equity should be sufficient to meet our contractual obligations , capital expenditures , working capital needs , dividend payments , debt requirements and to finance future acquisitions . outlook as part of our long-term growth strategy , we continue our efforts to expand our market presence by opening or expanding facilities in strategic areas and realizing synergies within our business lines subject to client demand and market conditions . we believe our market presence provides us a unique opportunity to service clients who have global operations whether they are international oil companies , national oil companies , or independent oil companies . our major clients continue to focus on capital management , return on invested capital ( “ roic ” ) , free cash flow , and returning capital back to their shareholders , as opposed to a focus on production growth at any cost . the companies adopting value versus volume metrics tend to be the more technologically sophisticated operators and form the foundation of core lab 's worldwide client base . we expect to benefit from our clients ' shift in focus from strictly production growth to employing higher technological solutions in their efforts to maximize economic production growth and estimated ultimate recovery ( `` eur `` ) . during the fourth quarter of 2019 , as reported by the international energy agency ( “ iea ” ) , the organization of the petroleum exporting countries ( “ opec ” ) determined additional crude-oil production cuts were required in order to support a more balanced market for crude-oil supply market . additional crude-oil supply will likely come from guyana , brazil , norway and the u.s. although crude-oil production in the u.s. has grown over the past several years , the rate of growth has declined over the past two years . 25 these factors associated with the global crude - oil market are proj ected to create a tighter crude- oil market into the second half of 2020 . a stronger crude - oil market will continue to support current pricing levels for crude oil and a more sustained level of capital investment in long-term international projects . these international investments are critical , as new field development is required to replace the decline in production from mature fields . as mentioned above , we believe operators will continue to manage their capital spending within approved budgets and maintain their focus on generating free cash flow . this was apparent during the fourth quarter of 2019 with the notable declines in both the u.s. onshore rig count and completion activity . as a result , core believes the u.s. onshore activity in 2020 will continue to be constrained by these factors . core lab expects international field development spending will be funded largely from operating budgets . international recovery on a more broad-based scope is expected to improve as 2020 unfolds . reservoir description continues to discuss international projects with clients , which are in alignment with final investment decisions ( “ fids ” ) previously announced . the revenue opportunity for reservoir description occurs once the well has been drilled and core and fluid samples are recovered from the well and analyzed . activity levels and revenue opportunities from these fids and the emerging international recovery are expected to have a positive impact on financial performance in 2020. critical accounting estimates the preparation of financial statements in accordance with u.s. gaap requires us to make certain estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of assets and liabilities at the date of the financial statements and the reported amounts of revenue and expenses during the reporting period . we evaluate our estimates on an ongoing basis and determine the adequacy of our estimates based on our historical experience and various other assumptions that we believe are reasonable under the circumstances . by nature , these judgments are subject to an inherent degree of uncertainty . we consider an accounting estimate to be critical if it is highly subjective and if changes in the estimate under different assumptions would result in a material impact on our financial condition and results of operations . the following transaction types require significant judgment and , therefore , are considered critical accounting policies as of december 31 , 2019. income taxes our income tax expense includes income taxes of the netherlands , the u.s. and other foreign countries as well as local , state and provincial income taxes . we recognize deferred tax assets or liabilities for the differences between the financial statement carrying amount and tax basis of assets and liabilities using enacted tax rates in effect for the years in which the asset is recovered or the liability is settled . we estimate the likelihood of the recoverability of our deferred tax assets ( particularly , net operating loss carry-forwards ) . any valuation allowance recorded is based on estimates and assumptions of taxable income into the future and a determination is made of the magnitude of deferred tax assets which are more likely than not to be realized . valuation allowances of our net deferred tax assets aggregated to $ 6.2 million and $ 9.7 million at december 31 , 2019 and 2018 , respectively . if these estimates and related assumptions

cash flows the following table summarizes cash flows for the years ended december 31 , 2019 , 2018 and 2017 ( in thousands ) : replace_table_token_6_th the decreases in cash provided by operating activities in 2019 compared to 2018 was primarily due to decreased operating income as the activity levels for the u.s. onshore oil and gas market declined . the decrease in cash flow from operations during 2018 was primarily due to an increase in working capital , which was impacted by the increase in inventory to support the expansion of new product lines associated with the acquisition of guardian . 23 cash used in investing activities in 2019 decreased $ 65.0 million compared to 2018. capital expenditures were comparable for 2019 and 2018 at approximately $ 22 million each year . however , 2018 included an acquisition increasing the cash used in investing activities by $ 48.9 million , and 2019 included proceeds from the divestiture of two businesses that decreased the cash used in investing activities by $ 17.8 million . cash used in investing activities in 2018 increased $ 50.1 million compared to 2017 primarily as a result of an acquisition for $ 48.9 million in 2018. cash used in financing activities in 2019 increased $ 43.4 million compared to 2018 , and decreased $ 61.6 million in 2018 compared to 2017. during 2019 , we used $ 3.3 million to repurchase our common shares , $ 97.6 million to pay dividends , and increased our debt balance by $ 15 million . during 2018 , we used $ 7.5 million to repurchase our common shares , $ 97.3 million to pay dividends , and increased our debt balance by $ 64 million , primarily to fund the acquisition of a business in 2018 for $ 48.9 million . during 2017 , we used $ 16.9 million to repurchase our common shares , $ 97.1 million to pay dividends , and increased our debt balance by $ 10 million . during 2019 , we repurchased 71,700 shares of our common stock for an aggregate amount of $ 3.3 million , or an average price of $ 46.14 per share .


 Write a concise suspicious activity report of the following text delimited by triple backquotes. Return your response as a formal report which covers the key points highlighting the location,dates,entity names and account holder information in chronological order of the text.
     ```cash flows the following table summarizes cash flows for the years ended december 31 , 2019 , 2018 and 2017 ( in thousands ) : replace_table_token_6_th the decreases in cash provided by operating activities in 2019 compared to 2018 was primarily due to decreased operating income as the activity levels for the u.s. onshore oil and gas market declined . the decrease in cash flow from operations during 2018 was primarily due to an increase in working capital , which was impacted by the increase in inventory to support the expansion of new product lines associated with the acquisition of guardian . 23 cash used in investing activities in 2019 decreased $ 65.0 million compared to 2018. capital expenditures were comparable for 2019 and 2018 at approximately $ 22 million each year . however , 2018 included an acquisition increasing the cash used in investing activities by $ 48.9 million , and 2019 included proceeds from the divestiture of two businesses that decreased the cash used in investing activities by $ 17.8 million . cash used in investing activities in 2018 increased $ 50.1 million compared to 2017 primarily as a result of an acquisition for $ 48.9 million in 2018. cash used in financing activities in 2019 increased $ 43.4 million compared to 2018 , and decreased $ 61.6 million in 2018 compared to 2017. during 2019 , we used $ 3.3 million to repurchase our common shares , $ 97.6 million to pay dividends , and increased our debt balance by $ 15 million . during 2018 , we used $ 7.5 million to repurchase our common shares , $ 97.3 million to pay dividends , and increased our debt balance by $ 64 million , primarily to fund the acquisition of a business in 2018 for $ 48.9 million . during 2017 , we used $ 16.9 million to repurchase our common shares , $ 97.1 million to pay dividends , and increased our debt balance by $ 10 million . during 2019 , we repurchased 71,700 shares of our common stock for an aggregate amount of $ 3.3 million , or an average price of $ 46.14 per share .
```    
 Suspicious Activity Report : ( 4 ) average daily and year-end europe brent crude spot price as reported by the u.s. energy information administration . ( 5 ) average daily and year-end henry hub natural gas spot price as reported by the u.s. energy information administration . the prices for both wti and brent crude oil showed improvement during 2017 and continued to strengthen through most of 2018 ; however , they decreased significantly during the last quarter of 2018. in 2019 , crude-oil prices improved during the first few months , and became more stable during the second half of the year . the end result was the average price for crude oil in 2019 was approximately 10 % lower than the average price for 2018. in general , activities associated with the exploration of oil and gas in the u.s. onshore market are more sensitive to changes in the crude-oil commodity prices , as opposed to larger international and offshore projects which take multiple years to plan and develop , and once announced and started , will continue through completion , despite changes in the current price of crude oil . the improvement in crude-oil prices in 2017 and 17 most of 2018 led to elevated levels in u.s. onshore activities associated with both the exploration and production of crude oil . additionally , during this time period , public announcements of investments in larger international and offshore projects were elevated and activity levels began to improve in 2018 and continued to improve into 2019. however , the continued vola tility and lower level of crude- oil prices in the last quarter of 2018 and during 2019 did negatively impact the activity levels in the u.s. onshore market which decreased in 2019. information published by the u.s. energy information administration ( “ eia ” ) , shows that the inventory of wells drilled but uncompleted ( a “ duc ” well ) was 6,566 as of december 31 , 2017 , increasing to a peak in february 2019 at approximately 8,500 , and ending 2019 at 7,573. this data indicates that during the period of higher activity in 2018 , operators were drilling wells but not completing them as the duc inventory grew . however , as activity levels began to fall in late 2018 and into 2019 , and operators began to drill fewer new wells , they were also completing some of the wells that had been previously drilled , which is reflected in the lower duc inventory at december 2019. in north america , the land-based rig count increased 45 % during 2017 and another 19 % during 2018 , which had a positive impact for both services and product sales to this market over this time period . the build in levels of activities on development projects and producing fields in the u.s. unconventional reservoirs during 2017 continued to strengthen during most of 2018 , until october 2018 when the commodity price weakened significantly and activity levels decreased . the lower commodity prices in 2019 led to a 10 % decrease in the annual average land-based rig count and a decline in u.s. based activities in 2019. outside of north america , activities associated with the exploration for and production of oil dropped to current lower levels during the industry downturn which began at the end of 2014. although activities have not yet increased , we believe these markets have shown signs of recovery for 2020 and beyond as our clients have announced new capital investment projects throughout 2017 , 2018 and 2019. results of operations operating results for the year ended december 31 , 2019 compared to the years ended december 31 , 2018 and 2017 we evaluate our operating results by analyzing revenue , operating income and operating income margin ( defined as operating income divided by total revenue ) . since we have a relatively fixed cost structure , decreases in revenue generally translate into lower operating income results . results for the years ended december 31 , 2019 , 2018 and 2017 are summarized in the following chart : 18 results of operations as a percentage of applicable revenue for the years ended december 31 , 2019 , 2018 and 2017 are as follows ( in thousands , except for per share information ) : 2019 / 2018 2018 / 2017 revenue : 2019 2018 2017 % change services $ 474,193 71.0 % $ 486,820 69.5 % $ 480,264 74.1 % ( 2.6 ) % 1.4 % product sales 194,017 29.0 % 214,026 30.5 % 167,555 25.9 % ( 9.3 ) % 27.7 % total revenue 668,210 100.0 % 700,846 100.0 % 647,819 100.0 % ( 4.7 ) % 8.2 % operating expenses : cost of services * ( 1 ) 345,641 72.9 % 343,833 70.6 % 333,365 69.4 % 0.5 % 3.1 % cost of product sales * ( 1 ) 149,938 77.3 % 153,131 71.5 % 131,593 78.5 % ( 2.1 ) % 16.4 % total cost of services and product sales 495,579 74.2 % 496,964 70.9 % 464,958 71.8 % ( 0.3 ) % 6.9 % general and administrative expenses ( 1 ) 48,023 7.2 % 62,910 9.0 % 47,737 7.4 % ( 23.7 ) % 31.8 % depreciation and amortization 22,605 3.4 % 23,087 3.3 % 24,524 3.8 % ( 2.1 ) % ( 5.9 ) % other ( income ) expense , net 5,319 0.8 % ( 737 ) ( 0.1 ) % 632 0.1 % nm nm operating income 96,684 14.5 % 118,622 16.9 % 109,968 17.0 % ( 18.5 ) % 7.9 % interest expense 14,690 2.2 % 13,328 1.9 % 10,734 1.7 % 10.2 % 24.2 % income before income tax expense 81,994 12.3 % 105,294 15.0 % 99,234 15.3 % ( 22.1 ) % 6.1 % income tax expense ( benefit ) ( 12,290 ) ( 1.8 ) % 25,447 3.6 % 18,249 2.8 % nm 39.4 % income from continuing operations 94,284 14.1 % story_separator_special_tag our ability to continue these initiatives depends on , among other things , market conditions and our ability to generate free cash flow . our ability to maintain and increase our operating income and cash flows is largely dependent upon continued investing activities . we are a netherlands holding company and substantially all of our operations are conducted through subsidiaries . consequently , our cash flow depends upon the ability of our subsidiaries to pay cash dividends or otherwise distribute or advance funds to us . we believe our future cash flows from operating activities , supplemented by our borrowing capacity under existing facilities and our ability to issue additional equity should be sufficient to meet our contractual obligations , capital expenditures , working capital needs , dividend payments , debt requirements and to finance future acquisitions . outlook as part of our long-term growth strategy , we continue our efforts to expand our market presence by opening or expanding facilities in strategic areas and realizing synergies within our business lines subject to client demand and market conditions . we believe our market presence provides us a unique opportunity to service clients who have global operations whether they are international oil companies , national oil companies , or independent oil companies . our major clients continue to focus on capital management , return on invested capital ( “ roic ” ) , free cash flow , and returning capital back to their shareholders , as opposed to a focus on production growth at any cost . the companies adopting value versus volume metrics tend to be the more technologically sophisticated operators and form the foundation of core lab 's worldwide client base . we expect to benefit from our clients ' shift in focus from strictly production growth to employing higher technological solutions in their efforts to maximize economic production growth and estimated ultimate recovery ( `` eur `` ) . during the fourth quarter of 2019 , as reported by the international energy agency ( “ iea ” ) , the organization of the petroleum exporting countries ( “ opec ” ) determined additional crude-oil production cuts were required in order to support a more balanced market for crude-oil supply market . additional crude-oil supply will likely come from guyana , brazil , norway and the u.s. although crude-oil production in the u.s. has grown over the past several years , the rate of growth has declined over the past two years . 25 these factors associated with the global crude - oil market are proj ected to create a tighter crude- oil market into the second half of 2020 . a stronger crude - oil market will continue to support current pricing levels for crude oil and a more sustained level of capital investment in long-term international projects . these international investments are critical , as new field development is required to replace the decline in production from mature fields . as mentioned above , we believe operators will continue to manage their capital spending within approved budgets and maintain their focus on generating free cash flow . this was apparent during the fourth quarter of 2019 with the notable declines in both the u.s. onshore rig count and completion activity . as a result , core believes the u.s. onshore activity in 2020 will continue to be constrained by these factors . core lab expects international field development spending will be funded largely from operating budgets . international recovery on a more broad-based scope is expected to improve as 2020 unfolds . reservoir description continues to discuss international projects with clients , which are in alignment with final investment decisions ( “ fids ” ) previously announced . the revenue opportunity for reservoir description occurs once the well has been drilled and core and fluid samples are recovered from the well and analyzed . activity levels and revenue opportunities from these fids and the emerging international recovery are expected to have a positive impact on financial performance in 2020. critical accounting estimates the preparation of financial statements in accordance with u.s. gaap requires us to make certain estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of assets and liabilities at the date of the financial statements and the reported amounts of revenue and expenses during the reporting period . we evaluate our estimates on an ongoing basis and determine the adequacy of our estimates based on our historical experience and various other assumptions that we believe are reasonable under the circumstances . by nature , these judgments are subject to an inherent degree of uncertainty . we consider an accounting estimate to be critical if it is highly subjective and if changes in the estimate under different assumptions would result in a material impact on our financial condition and results of operations . the following transaction types require significant judgment and , therefore , are considered critical accounting policies as of december 31 , 2019. income taxes our income tax expense includes income taxes of the netherlands , the u.s. and other foreign countries as well as local , state and provincial income taxes . we recognize deferred tax assets or liabilities for the differences between the financial statement carrying amount and tax basis of assets and liabilities using enacted tax rates in effect for the years in which the asset is recovered or the liability is settled . we estimate the likelihood of the recoverability of our deferred tax assets ( particularly , net operating loss carry-forwards ) . any valuation allowance recorded is based on estimates and assumptions of taxable income into the future and a determination is made of the magnitude of deferred tax assets which are more likely than not to be realized . valuation allowances of our net deferred tax assets aggregated to $ 6.2 million and $ 9.7 million at december 31 , 2019 and 2018 , respectively . if these estimates and related assumptions

