2018 financial highlights among other financial highlights , for the year ended december 31 , 2018 : revenue increased $ 722.7 million , or 73.6 % , to $ 1,704.6 million , as compared to $ 981.9 million for the year ended december 31 , 2017 , primarily as a result of the increase in our fleet size ; cost of services ( exclusive of depreciation and amortization ) increased $ 456.8 million or 56.1 % to $ 1,270.6 million , as compared to $ 813.8 million for the year ended december 31 , 2017 , primarily as a result of the increase in fleet size , resulting in higher activity levels . cost of services as a percentage of revenue decreased to 74.5 % in 2018 compared to 82.9 % for the year ended december 31 , 2017 ; general and administrative expenses , inclusive of stock-based compensation ( “ g & a ” ) , increased $ 4.7 million , or 9.6 % to $ 54.0 million , as compared to $ 49.2 million for the december 31 , 2017 . g & a as a percentage of revenue decreased to 3.2 % in 2018 from 5.0 % for the year ended december 31 , 2017 ; diluted net income per common share was $ 2.00 , compared to $ 0.16 for the year ended december 31 , 2017 . 2019 outlook in 2019 , we continue to focus on providing best-in-class service to our customers , helping our customer improve their well economics while continuing to enhance the company 's profitability . we expect to achieve these objectives through : continuing to enhance our dedicated customer model to drive production efficiencies ; maintaining full utilization of our hydraulic fracturing fleets ; pursuing operational efficiencies and cost reduction strategies ; pursuing expansion opportunities for our non-hydraulic fracturing operations ; maintaining our existing relationships with our vendors and developing strategic relationships with new suppliers to ensure continuity ; exploring potential opportunities for mergers or acquisitions , focused on our growth , market opportunities and creating value to our shareholders . 32 our assets and operations through our pressure pumping segment , which includes cementing operations , we primarily provide hydraulic fracturing services ( inclusive of acidizing services ) to e & p companies in the permian basin . our modern hydraulic fracturing fleet has been designed to handle permian basin specific operating conditions and the region 's increasingly high‑intensity well completions , which are characterized by longer horizontal wellbores , more frac stages per lateral and increasing amounts of proppant per well . we have fully maintained our equipment throughout the recent industry downturn to ensure optimal performance and reliability . in addition to our core pressure pumping segment operations , we also offer a suite of complementary well completion and production services , including coiled tubing and flowback services . we believe these complementary services create operational efficiencies for our customers and allow us to capture a greater portion of their capital spending across the lifecycle of a well . additionally , we believe that these complementary services should benefit from a continued industry recovery and that we are well positioned to continue expanding these offerings in response to our customers ' increasing service needs and spending levels . how we generate revenue we generate revenue primarily through our pressure pumping segment , and more specifically , by providing hydraulic fracturing services to our customers . we own and operate a fleet of mobile hydraulic fracturing units and other auxiliary equipment to perform fracturing services . we also provide personnel and services that are tailored to meet each of our customers ' needs . we charge our customers on a per‑job basis , in which we set pricing terms after receiving full specifications for the requested job , including the lateral length of the customer 's wellbore , the number of frac stages per well , the amount of proppant to be employed and other parameters of the job . in addition to hydraulic fracturing services , we generate revenue through the complementary services that we provide to our customers , including cementing , coiled tubing and flowback services . these complementary services are provided through various contractual arrangements , including on a turnkey contract basis , in which we set a price to perform a particular job , or a daywork contract basis , in which we are paid a set price per day for our services . we are also sometimes paid by the hour for these complementary services . our revenue , profitability and cash flows are highly dependent upon prevailing crude oil prices and expectations about future prices . for many years , oil prices and markets have been extremely volatile . prices are affected by many factors beyond our control . west texas intermediate ( “ wti ” ) oil prices which declined significantly in 2015 and 2016 , but recovered somewhat during 2017 and 2018. the average wti oil prices per barrel was $ 65.1 , $ 50.8 and $ 43.3 for the years ended december 31 , 2018 , 2017 and 2016 , respectively . as a result of the recent recovery in oil prices , our industry has experienced a significant increase in both drilling and pressure pumping activity levels . looking forward , if oil prices increase , we believe u.s. rig counts will also increase , which may result in an increase in demand for drilling and pressure pumping services . higher oil and natural gas prices do not necessarily result in increased activity because demand for our services is generally driven by our customers ' expectations of future oil and natural gas prices , as well as rig count . story_separator_special_tag we calculate depreciation of property and equipment using the straight-line method . property and equipment impairment expense . there was no property and equipment impairment expense during the year ended december 31 , 2017 , compared to $ 6.3 million during the year ended december 31 , 2016. the non‑cash impairment expense in 2016 was associated with our drilling rigs , and was recognized as a result of depressed commodity prices and a negative future near‑term outlook for these assets . goodwill impairment expense . there was no goodwill impairment expense during the year ended december 31 , 2017 , compared to $ 1.2 million during the year ended december 31 , 2016. the non‑cash goodwill impairment expense in 2016 was as a result of the write‑down of goodwill related to our surface drilling reporting unit . loss on disposal of assets . loss on the disposal of assets increased 73.5 % , or $ 16.6 million , to $ 39.1 million for the year ended december 31 , 2017 , as compared to $ 22.5 million for the year ended december 31 , 2016. the increase was primarily attributable to greater service intensity of jobs completed , coupled with higher fleet size , activity levels and utilization of our equipment . interest expense . interest expense decreased 64.0 % , or $ 13.0 million , to $ 7.3 million for the year ended december 31 , 2017 , as compared to $ 20.4 million for the year ended december 31 , 2016. the decrease in interest expense was primarily attributable to a reduction in our average debt balance during 2017 due to the early retirement of our term loan and revolving credit facility in the first quarter of 2017. gain on extinguishment of debt . there was no debt extinguishment gain or loss during the year ended december 31 , 2017 , compared to the gain on extinguishment of debt , net of cost , of $ 7.0 million during the year ended december 31 , 2016. the gain on extinguishment of debt during 2016 was as a result of the auction process with our lenders to repurchase $ 37.5 million of our term loan at a 20 % discount to par value . 40 other expense . other expense was $ 1.0 million for the year ended december 31 , 2017 , as compared to $ 0.3 million for the year ended december 31 , 2016. the increase was primarily attributable to an increase in lenders related expenses , non-recurring listing related expenses , and partially offset by an increase in the unrealized gain resulting from the change in the fair value of our interest rate swap liability at december 31 , 2017 compared to december 31 , 2016. income tax expense/ ( benefit ) . income tax expense was $ 3.1 million for the year ended december 31 , 2017 , compared to income tax benefit of $ 28.0 million , for the year ended december 31 , 2016. the change from an income tax benefit to income tax expense is primarily due to the company 's reporting income before taxes during the year ended december 31 , 2017 , compared to a loss before taxes recorded during the year ended december 31 , 2016. the income before taxes generated is attributable to the increase in our revenue during the year ended december 31 , 2017 , compared to december 31 , 2016. additionally , the income tax expense during the year ended december 31 , 2017 , included a one-time deferred tax benefit offset of $ 3.4 million , resulting from the u.s. government enacted tax legislation commonly referred to as the tax cuts and jobs act ( “ tax act ” ) . liquidity and capital resources our liquidity is currently provided by ( i ) existing cash balances , ( ii ) operating cash flows and ( iii ) borrowings under our abl credit facility . our primary uses of cash will be to continue to fund our operations , support growth opportunities and satisfy debt payments . as of december 31 , 2018 , our total liquidity consists of cash and cash equivalents of $ 132.7 million , and $ 125.0 million of availability under our abl credit facility . there can be no assurance that operations and other capital resources will provide cash in sufficient amounts to maintain planned or future levels of capital expenditures . future cash flows are subject to a number of variables , and are highly dependent on the drilling , completion , and production activity by our customers , which in turn is highly dependent on oil and gas prices . depending upon market conditions and other factors , we may issue equity and debt securities or take other actions necessary to fund our business or meet our future long-term liquidity requirements . story_separator_special_tag the abl credit facility balance outstanding is exclusive of future commitment fees , interest or other fees since our potential future obligations thereunder are based on future events and can not be reasonably estimated . ( 2 ) operating leases include agreements for various office and maintenance locations . 43 recent accounting pronouncements disclosure concerning recently issued accounting standards is incorporated by reference to note 2 of our consolidated financial statements contained in this form 10-k. critical accounting policies and estimates the discussion and analysis of our financial condition and results of operations is based on our consolidated financial statements , which have been prepared in accordance with accounting principles generally acceptable in the united states of america . the preparation of these financial statements requires us to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the dates of the financial statements and the reported revenues and expenses during the years . we evaluate these estimates and assumptions on an ongoing basis and base our estimates on historical experience

cash and cash flows the following table sets forth our net cash provided by ( used in ) operating , investing and financing activities during the year at december 31 , 2018 , 2017 and 2016 , respectively . replace_table_token_9_th operating activities net cash provided by operating activities was $ 393.1 million for the year ended december 31 , 2018 , as compared to $ 109.3 million for the year ended december 31 , 2017 . the net increase of $ 283.8 million was primarily due to the increase in our revenue generating assets ( fleet size ) , which has resulted in increases in revenue and net income in the year , offset by our working capital needs resulting from higher fleet size and expanding activity levels . net cash provided by operating activities was $ 109.3 million for the year ended december 31 , 2017 , as compared to $ 10.7 million for the year ended december 31 , 2016. the net increase of $ 98.6 million was primarily due to an increase in revenue and net income in the year , resulting from an increase in customer activity , fleet size and demand for our services , and partially offset by the increase in our working capital needs resulting from higher fleet size and expanding activity levels . 41 investing activities net cash used in investing activities decreased to $ 280.6 million for the year ended december 31 , 2018 , from $ 281.5 million for the year ended december 31 , 2017 . the slight decrease was primarily attributable to the decrease in cash payment for capital expenditures during the year ended december 31 , 2018 , compared to the year ended december 31 , 2017 . net cash used in investing activities increased to $ 281.5 million for the year ended december 31 , 2017 , from $ 41.7 million for the year ended december 31 , 2016. the increase was primarily attributable to the additional hydraulic fracturing units and other ancillary equipment purchased and a marginal increase in maintenance capital expenditures , during the year ended december 31 , 2017 , compared to the year ended december 31 , 2016.


 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 and cash flows the following table sets forth our net cash provided by ( used in ) operating , investing and financing activities during the year at december 31 , 2018 , 2017 and 2016 , respectively . replace_table_token_9_th operating activities net cash provided by operating activities was $ 393.1 million for the year ended december 31 , 2018 , as compared to $ 109.3 million for the year ended december 31 , 2017 . the net increase of $ 283.8 million was primarily due to the increase in our revenue generating assets ( fleet size ) , which has resulted in increases in revenue and net income in the year , offset by our working capital needs resulting from higher fleet size and expanding activity levels . net cash provided by operating activities was $ 109.3 million for the year ended december 31 , 2017 , as compared to $ 10.7 million for the year ended december 31 , 2016. the net increase of $ 98.6 million was primarily due to an increase in revenue and net income in the year , resulting from an increase in customer activity , fleet size and demand for our services , and partially offset by the increase in our working capital needs resulting from higher fleet size and expanding activity levels . 41 investing activities net cash used in investing activities decreased to $ 280.6 million for the year ended december 31 , 2018 , from $ 281.5 million for the year ended december 31 , 2017 . the slight decrease was primarily attributable to the decrease in cash payment for capital expenditures during the year ended december 31 , 2018 , compared to the year ended december 31 , 2017 . net cash used in investing activities increased to $ 281.5 million for the year ended december 31 , 2017 , from $ 41.7 million for the year ended december 31 , 2016. the increase was primarily attributable to the additional hydraulic fracturing units and other ancillary equipment purchased and a marginal increase in maintenance capital expenditures , during the year ended december 31 , 2017 , compared to the year ended december 31 , 2016.
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 Suspicious Activity Report : 2018 financial highlights among other financial highlights , for the year ended december 31 , 2018 : revenue increased $ 722.7 million , or 73.6 % , to $ 1,704.6 million , as compared to $ 981.9 million for the year ended december 31 , 2017 , primarily as a result of the increase in our fleet size ; cost of services ( exclusive of depreciation and amortization ) increased $ 456.8 million or 56.1 % to $ 1,270.6 million , as compared to $ 813.8 million for the year ended december 31 , 2017 , primarily as a result of the increase in fleet size , resulting in higher activity levels . cost of services as a percentage of revenue decreased to 74.5 % in 2018 compared to 82.9 % for the year ended december 31 , 2017 ; general and administrative expenses , inclusive of stock-based compensation ( “ g & a ” ) , increased $ 4.7 million , or 9.6 % to $ 54.0 million , as compared to $ 49.2 million for the december 31 , 2017 . g & a as a percentage of revenue decreased to 3.2 % in 2018 from 5.0 % for the year ended december 31 , 2017 ; diluted net income per common share was $ 2.00 , compared to $ 0.16 for the year ended december 31 , 2017 . 2019 outlook in 2019 , we continue to focus on providing best-in-class service to our customers , helping our customer improve their well economics while continuing to enhance the company 's profitability . we expect to achieve these objectives through : continuing to enhance our dedicated customer model to drive production efficiencies ; maintaining full utilization of our hydraulic fracturing fleets ; pursuing operational efficiencies and cost reduction strategies ; pursuing expansion opportunities for our non-hydraulic fracturing operations ; maintaining our existing relationships with our vendors and developing strategic relationships with new suppliers to ensure continuity ; exploring potential opportunities for mergers or acquisitions , focused on our growth , market opportunities and creating value to our shareholders . 32 our assets and operations through our pressure pumping segment , which includes cementing operations , we primarily provide hydraulic fracturing services ( inclusive of acidizing services ) to e & p companies in the permian basin . our modern hydraulic fracturing fleet has been designed to handle permian basin specific operating conditions and the region 's increasingly high‑intensity well completions , which are characterized by longer horizontal wellbores , more frac stages per lateral and increasing amounts of proppant per well . we have fully maintained our equipment throughout the recent industry downturn to ensure optimal performance and reliability . in addition to our core pressure pumping segment operations , we also offer a suite of complementary well completion and production services , including coiled tubing and flowback services . we believe these complementary services create operational efficiencies for our customers and allow us to capture a greater portion of their capital spending across the lifecycle of a well . additionally , we believe that these complementary services should benefit from a continued industry recovery and that we are well positioned to continue expanding these offerings in response to our customers ' increasing service needs and spending levels . how we generate revenue we generate revenue primarily through our pressure pumping segment , and more specifically , by providing hydraulic fracturing services to our customers . we own and operate a fleet of mobile hydraulic fracturing units and other auxiliary equipment to perform fracturing services . we also provide personnel and services that are tailored to meet each of our customers ' needs . we charge our customers on a per‑job basis , in which we set pricing terms after receiving full specifications for the requested job , including the lateral length of the customer 's wellbore , the number of frac stages per well , the amount of proppant to be employed and other parameters of the job . in addition to hydraulic fracturing services , we generate revenue through the complementary services that we provide to our customers , including cementing , coiled tubing and flowback services . these complementary services are provided through various contractual arrangements , including on a turnkey contract basis , in which we set a price to perform a particular job , or a daywork contract basis , in which we are paid a set price per day for our services . we are also sometimes paid by the hour for these complementary services . our revenue , profitability and cash flows are highly dependent upon prevailing crude oil prices and expectations about future prices . for many years , oil prices and markets have been extremely volatile . prices are affected by many factors beyond our control . west texas intermediate ( “ wti ” ) oil prices which declined significantly in 2015 and 2016 , but recovered somewhat during 2017 and 2018. the average wti oil prices per barrel was $ 65.1 , $ 50.8 and $ 43.3 for the years ended december 31 , 2018 , 2017 and 2016 , respectively . as a result of the recent recovery in oil prices , our industry has experienced a significant increase in both drilling and pressure pumping activity levels . looking forward , if oil prices increase , we believe u.s. rig counts will also increase , which may result in an increase in demand for drilling and pressure pumping services . higher oil and natural gas prices do not necessarily result in increased activity because demand for our services is generally driven by our customers ' expectations of future oil and natural gas prices , as well as rig count . story_separator_special_tag we calculate depreciation of property and equipment using the straight-line method . property and equipment impairment expense . there was no property and equipment impairment expense during the year ended december 31 , 2017 , compared to $ 6.3 million during the year ended december 31 , 2016. the non‑cash impairment expense in 2016 was associated with our drilling rigs , and was recognized as a result of depressed commodity prices and a negative future near‑term outlook for these assets . goodwill impairment expense . there was no goodwill impairment expense during the year ended december 31 , 2017 , compared to $ 1.2 million during the year ended december 31 , 2016. the non‑cash goodwill impairment expense in 2016 was as a result of the write‑down of goodwill related to our surface drilling reporting unit . loss on disposal of assets . loss on the disposal of assets increased 73.5 % , or $ 16.6 million , to $ 39.1 million for the year ended december 31 , 2017 , as compared to $ 22.5 million for the year ended december 31 , 2016. the increase was primarily attributable to greater service intensity of jobs completed , coupled with higher fleet size , activity levels and utilization of our equipment . interest expense . interest expense decreased 64.0 % , or $ 13.0 million , to $ 7.3 million for the year ended december 31 , 2017 , as compared to $ 20.4 million for the year ended december 31 , 2016. the decrease in interest expense was primarily attributable to a reduction in our average debt balance during 2017 due to the early retirement of our term loan and revolving credit facility in the first quarter of 2017. gain on extinguishment of debt . there was no debt extinguishment gain or loss during the year ended december 31 , 2017 , compared to the gain on extinguishment of debt , net of cost , of $ 7.0 million during the year ended december 31 , 2016. the gain on extinguishment of debt during 2016 was as a result of the auction process with our lenders to repurchase $ 37.5 million of our term loan at a 20 % discount to par value . 40 other expense . other expense was $ 1.0 million for the year ended december 31 , 2017 , as compared to $ 0.3 million for the year ended december 31 , 2016. the increase was primarily attributable to an increase in lenders related expenses , non-recurring listing related expenses , and partially offset by an increase in the unrealized gain resulting from the change in the fair value of our interest rate swap liability at december 31 , 2017 compared to december 31 , 2016. income tax expense/ ( benefit ) . income tax expense was $ 3.1 million for the year ended december 31 , 2017 , compared to income tax benefit of $ 28.0 million , for the year ended december 31 , 2016. the change from an income tax benefit to income tax expense is primarily due to the company 's reporting income before taxes during the year ended december 31 , 2017 , compared to a loss before taxes recorded during the year ended december 31 , 2016. the income before taxes generated is attributable to the increase in our revenue during the year ended december 31 , 2017 , compared to december 31 , 2016. additionally , the income tax expense during the year ended december 31 , 2017 , included a one-time deferred tax benefit offset of $ 3.4 million , resulting from the u.s. government enacted tax legislation commonly referred to as the tax cuts and jobs act ( “ tax act ” ) . liquidity and capital resources our liquidity is currently provided by ( i ) existing cash balances , ( ii ) operating cash flows and ( iii ) borrowings under our abl credit facility . our primary uses of cash will be to continue to fund our operations , support growth opportunities and satisfy debt payments . as of december 31 , 2018 , our total liquidity consists of cash and cash equivalents of $ 132.7 million , and $ 125.0 million of availability under our abl credit facility . there can be no assurance that operations and other capital resources will provide cash in sufficient amounts to maintain planned or future levels of capital expenditures . future cash flows are subject to a number of variables , and are highly dependent on the drilling , completion , and production activity by our customers , which in turn is highly dependent on oil and gas prices . depending upon market conditions and other factors , we may issue equity and debt securities or take other actions necessary to fund our business or meet our future long-term liquidity requirements . story_separator_special_tag the abl credit facility balance outstanding is exclusive of future commitment fees , interest or other fees since our potential future obligations thereunder are based on future events and can not be reasonably estimated . ( 2 ) operating leases include agreements for various office and maintenance locations . 43 recent accounting pronouncements disclosure concerning recently issued accounting standards is incorporated by reference to note 2 of our consolidated financial statements contained in this form 10-k. critical accounting policies and estimates the discussion and analysis of our financial condition and results of operations is based on our consolidated financial statements , which have been prepared in accordance with accounting principles generally acceptable in the united states of america . the preparation of these financial statements requires us to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the dates of the financial statements and the reported revenues and expenses during the years . we evaluate these estimates and assumptions on an ongoing basis and base our estimates on historical experience

