our federal services group also provides energy consulting services and it solutions and services with a focus on medical and health related fields for various dod and federal civilian agencies , including the united states department of energy ( `` doe `` ) ; the social security administration ; the national institutes of health ( `` nih `` ) ; customers in the military health system ; and other government agencies and commercial clients . - 16 - concentration of revenues replace_table_token_6_th * our aviation group utilizes the federal services group 's fms program to sell its gas turbine mro services to the dod . management outlook aviation group we believe that our january 2019 acquisition of 1st choice aerospace will provide a significant opportunity for revenue and profit growth for our aviation group . 1st choice aerospace is expected to broaden our product lines and client base , particularly in the commercial aerospace market , and we see opportunities to strategically align 1st choice aerospace 's offerings with our existing domestic and international markets , including our recent singapore and european initiatives . for additional information regarding 1st choice aerospace , see note 17 `` subsequent events `` to our consolidated financial statement included below in item 8. our aviation group has demonstrated improved performance in 2018 , with contributions provided by both new and existing lines of business . we have increased revenue and operating profits on sales from new parts distribution and on mro services on engine accessories and components . our singapore operation began generating revenue in the second quarter as we extended new product lines to new end-user clients in the asia-pacific market , including commercial airlines . we extended key distribution agreements to other geographic markets . we believe these efforts will provide us with sustainable revenue sources with viable growth potential , and that the associated investment in increased inventory will be beneficial to our future results . we expect the addition of 1st choice aerospace to accelerate our improved results without materially increasing our inventory investment . while revenues , operating income , and inventory may experience fluctuations due to market demand and the mix of products sold , we are optimistic about the performance of our aviation group . supply chain management group our supply chain management group continues to make steady progress toward becoming a more diversified enterprise that is less reliant on a single large customer . parts sales and supply chain and inventory management support services to dod and commercial clients have shown steady increases as we capture new commercial customers . our commercial client base now includes companies in a wide array of businesses that have vehicle fleets required to meet mission critical delivery or service schedules . we also are capturing new customers and increasing revenue using e-commerce solutions . we look forward to further developing these new client relationships and expect them to reflect a more significant portion of our revenue in the future . revenues from the sale of parts to the usps declined about 3 % in 2018. we are closely monitoring the usps next-generation delivery vehicle ( “ ngdv ” ) procurement effort , which is progressing more slowly than the usps had previously expected . we are positioning ourselves to support newly procured vehicles eventually placed in service and aging vehicles that remain in service . while it will likely be several years before the ngdv is placed in service in significant numbers , the usps has begun some shorter-term annual vehicle acquisitions through the procurement of commercial off-the-shelf ( `` cots `` ) mass-market vehicles and the retirement of some of its aging cots vehicles . the turnover of these cots vehicles is the primary factor for the 3 % revenue decline in 2018. as the new cots vehicles begin to age , we expect the demand for replacement parts to keep them operating will return . as a matter of usps practice , we are a provider of replacement parts for all 215,000 usps vehicle fleet assets , including the cots vehicles . while we can not predict with certainty the impact of the usps ngdv procurement and concurrent retirement of older fleet assets on our future revenues , we believe that our years of service , unique knowledge of this client 's complex operational model and maintenance facility processes and procedures , and our superior performance strategically position us to continue to serve as a key vehicle fleet sustainment partner regardless of source or vintage . we expect to continue supporting usps during its comprehensive vehicle transition initiatives embracing emerging technologies spanning the next decade or longer . - 17 - federal services group the revenues from our fms program in 2018 declined due to the completion of the transfer of two frigates to taiwan in 2017 and procedural delays in the contracting process . our federal services group revenues were down in 2018 due to the fms revenue decline , completion of work on two of our u.s. army programs in 2017 , a reduction in work performed on our rrad ers contract in may 2018 due to a client directed reduction in force , and a decline in our energy , and management consulting work . despite these revenue challenges , our operating income has increased due to a gain on the sale of an it services contract , margin improvements on some of our u. s. army programs and the completion in 2017 of a contract that recorded a loss . in the third quarter of 2018 , we sold an it services contract that we had been awarded by the nih to a company with more extensive it client relationships . as a result , we were able to monetize the value of the contract while retaining the work we were performing and maintain our access to the contract for future potential work . tax cuts and jobs act public law no . story_separator_special_tag these costs will generally increase or decrease in conjunction with our level of products sold or contract work performed . costs and operating expenses also include expense for amortization of intangible assets acquired through our acquisitions . expense for amortization of acquisition related intangible assets is included in the segment results in which the acquisition is included . segment results also include expense for an allocation of corporate management costs . our costs and operating expenses decreased by approximately $ 61 million or 9 % in 2018 as compared to 2017. the change in costs and operating expenses resulted primarily from a decrease in our federal services group of approximately $ 74 million , an increase in our supply chain management group of approximately $ 3 million , and an increase in our aviation group of approximately $ 9 million . costs and expenses for 2018 included approximately $ 569 thousand associated with our acquisition of 1st choice aerospace in january 2019. our costs and operating expenses increased by approximately $ 66 million or 10 % in 2017 as compared to 2016. the change in costs and operating expenses resulted primarily from an increase in our federal services group of approximately $ 52 million , an increase in our supply chain management group of approximately $ 10 million , and an increase in our aviation group of approximately $ 4 million . our operating income for 2018 was relatively unchanged as compared to 2017 . operating group results included operating income increases for our federal services group of approximately $ 2.4 million and for our aviation group of approximately $ 1.4 million , and an operating income decrease for our supply chain management group of approximately $ 3.1 million . operating income for 2018 was decreased by approximately $ 569 thousand due to the costs and expenses associated with our acquisition of 1st choice aerospace in january 2019. our operating income increased by approximately $ 2.8 million or 5 % in 2017 as compared to 2016 . the change in operating income resulted primarily from changes in our operating group results and settlement of two material lawsuits . operating group results included an operating income increases for our federal services group of approximately $ 5.6 million and an operating income decreases for our aviation group of approximately $ 3.1 million and for our supply chain management group of approximately $ 878 thousand . our increase in revenue allowed us to allocate our corporate infrastructure costs over a larger revenue base , which benefited each operating group 's income . the combined effect of the lawsuit settlements resulted in a decrease in operating income of approximately $ 1.9 million for 2016. interest expense decreased approximately $ 258 thousand in 2018 as compared to 2017 and approximately $ 615 thousand in 2017 as compared to 2016 , primarily due to declines of our bank debt levels . interest expense also includes interest related to our executive and administrative headquarters facility lease . the amount of interest expense associated with our headquarters financing lease is approximately $ 1.4 million , $ 1.5 million and $ 1.6 million for 2018 , 2017 and 2016 , respectively . provision for income taxes our effective tax rate was 22.5 % for 2018 , 13.3 % for 2017 , and 35.7 % for 2016 . the tax act passed in december 2017 resulted in a decrease to our federal tax rate for 2018 to 21 % and lowered our cash tax payments for 2018. due to the tax act , we - 22 - recorded a one-time reduction in our deferred tax liabilities in the fourth quarter of 2017 that resulted in a reduction in our provision for income taxes of approximately $ 10.6 million for the year and lowered our effective tax rate for 2017. our tax rate is also affected by discrete items that may occur in any given year , but may not be consistent from year to year . in addition to state income taxes , certain tax credits and other items caused differences between our statutory u.s. federal income tax rate and our effective tax rate . other permanent differences and federal and state tax credits such as the work opportunity tax credit and a state educational improvement tax credit provided benefit to our tax rates for 2018 , 2017 and 2016 . supply chain management group results the results of operations for our supply chain management group are ( in thousands ) : replace_table_token_10_th revenues for our supply chain management group were substantially unchanged for 2018 , as compared to the prior year . revenues from sales to the usps declined approximately $ 4.9 million and revenues from sales to dod and commercial customers increased approximately $ 5.3 million or 16 % . costs and operating expenses for our supply chain management group increased approximately $ 3.4 million or 2 % and operating income decreased by approximately $ 3.1 million or 9 % for 2018 as compared to the prior year . the decrease in operating income was primarily attributable to market competition and a change in the mix of products sold . the products sold associated with our increasing dod and commercial customer revenues tend to lower our overall profit margins as our revenue mix changes . revenues for our supply chain management group increased approximately $ 9 million or 4 % for 2017 , as compared to the prior year . the revenue increase resulted primarily from an increase in sales to dod and commercial customers of approximately $ 9.6 million or 40 % . costs and operating expenses for our supply chain management group increased approximately $ 10 million or 6 % and operating income decreased by approximately $ 878 thousand or 3 % for 2017 as compared to the prior year . the increase in costs and operating expenses resulted primarily from an increase in products sold . - 23 - aviation group results the results of

liquidity our internal sources of liquidity are primarily from operating activities , specifically from changes in our level of revenues and associated inventory , accounts receivable and accounts payable , and from profitability . significant increases or decreases in revenues and inventory , accounts receivable and accounts payable can affect our liquidity . our inventory and accounts payable levels can be affected by the timing of large opportunistic inventory purchases . our accounts receivable and accounts payable levels can be affected by changes in the level of contract work we perform , by the timing of large materials purchases and subcontractor efforts used in our contracts , and by delays in the award of contractual coverage and funding and payments . government funding delays can cause delays in our ability to invoice for revenues earned , presenting a potential negative impact on our days sales outstanding . we also purchase property and equipment ; invest in expansion , improvement , and maintenance of our operational and administrative facilities ; and invest in the acquisition of other companies . our external financing consists of a loan agreement with a bank group that provides for a term loan , revolving loans and letters of credit . the loan agreement , which was amended in january 2018 and expires in january 2023 , has a term loan facility and a revolving loan facility .


 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.
     ```liquidity our internal sources of liquidity are primarily from operating activities , specifically from changes in our level of revenues and associated inventory , accounts receivable and accounts payable , and from profitability . significant increases or decreases in revenues and inventory , accounts receivable and accounts payable can affect our liquidity . our inventory and accounts payable levels can be affected by the timing of large opportunistic inventory purchases . our accounts receivable and accounts payable levels can be affected by changes in the level of contract work we perform , by the timing of large materials purchases and subcontractor efforts used in our contracts , and by delays in the award of contractual coverage and funding and payments . government funding delays can cause delays in our ability to invoice for revenues earned , presenting a potential negative impact on our days sales outstanding . we also purchase property and equipment ; invest in expansion , improvement , and maintenance of our operational and administrative facilities ; and invest in the acquisition of other companies . our external financing consists of a loan agreement with a bank group that provides for a term loan , revolving loans and letters of credit . the loan agreement , which was amended in january 2018 and expires in january 2023 , has a term loan facility and a revolving loan facility .
```    
 Suspicious Activity Report : our federal services group also provides energy consulting services and it solutions and services with a focus on medical and health related fields for various dod and federal civilian agencies , including the united states department of energy ( `` doe `` ) ; the social security administration ; the national institutes of health ( `` nih `` ) ; customers in the military health system ; and other government agencies and commercial clients . - 16 - concentration of revenues replace_table_token_6_th * our aviation group utilizes the federal services group 's fms program to sell its gas turbine mro services to the dod . management outlook aviation group we believe that our january 2019 acquisition of 1st choice aerospace will provide a significant opportunity for revenue and profit growth for our aviation group . 1st choice aerospace is expected to broaden our product lines and client base , particularly in the commercial aerospace market , and we see opportunities to strategically align 1st choice aerospace 's offerings with our existing domestic and international markets , including our recent singapore and european initiatives . for additional information regarding 1st choice aerospace , see note 17 `` subsequent events `` to our consolidated financial statement included below in item 8. our aviation group has demonstrated improved performance in 2018 , with contributions provided by both new and existing lines of business . we have increased revenue and operating profits on sales from new parts distribution and on mro services on engine accessories and components . our singapore operation began generating revenue in the second quarter as we extended new product lines to new end-user clients in the asia-pacific market , including commercial airlines . we extended key distribution agreements to other geographic markets . we believe these efforts will provide us with sustainable revenue sources with viable growth potential , and that the associated investment in increased inventory will be beneficial to our future results . we expect the addition of 1st choice aerospace to accelerate our improved results without materially increasing our inventory investment . while revenues , operating income , and inventory may experience fluctuations due to market demand and the mix of products sold , we are optimistic about the performance of our aviation group . supply chain management group our supply chain management group continues to make steady progress toward becoming a more diversified enterprise that is less reliant on a single large customer . parts sales and supply chain and inventory management support services to dod and commercial clients have shown steady increases as we capture new commercial customers . our commercial client base now includes companies in a wide array of businesses that have vehicle fleets required to meet mission critical delivery or service schedules . we also are capturing new customers and increasing revenue using e-commerce solutions . we look forward to further developing these new client relationships and expect them to reflect a more significant portion of our revenue in the future . revenues from the sale of parts to the usps declined about 3 % in 2018. we are closely monitoring the usps next-generation delivery vehicle ( “ ngdv ” ) procurement effort , which is progressing more slowly than the usps had previously expected . we are positioning ourselves to support newly procured vehicles eventually placed in service and aging vehicles that remain in service . while it will likely be several years before the ngdv is placed in service in significant numbers , the usps has begun some shorter-term annual vehicle acquisitions through the procurement of commercial off-the-shelf ( `` cots `` ) mass-market vehicles and the retirement of some of its aging cots vehicles . the turnover of these cots vehicles is the primary factor for the 3 % revenue decline in 2018. as the new cots vehicles begin to age , we expect the demand for replacement parts to keep them operating will return . as a matter of usps practice , we are a provider of replacement parts for all 215,000 usps vehicle fleet assets , including the cots vehicles . while we can not predict with certainty the impact of the usps ngdv procurement and concurrent retirement of older fleet assets on our future revenues , we believe that our years of service , unique knowledge of this client 's complex operational model and maintenance facility processes and procedures , and our superior performance strategically position us to continue to serve as a key vehicle fleet sustainment partner regardless of source or vintage . we expect to continue supporting usps during its comprehensive vehicle transition initiatives embracing emerging technologies spanning the next decade or longer . - 17 - federal services group the revenues from our fms program in 2018 declined due to the completion of the transfer of two frigates to taiwan in 2017 and procedural delays in the contracting process . our federal services group revenues were down in 2018 due to the fms revenue decline , completion of work on two of our u.s. army programs in 2017 , a reduction in work performed on our rrad ers contract in may 2018 due to a client directed reduction in force , and a decline in our energy , and management consulting work . despite these revenue challenges , our operating income has increased due to a gain on the sale of an it services contract , margin improvements on some of our u. s. army programs and the completion in 2017 of a contract that recorded a loss . in the third quarter of 2018 , we sold an it services contract that we had been awarded by the nih to a company with more extensive it client relationships . as a result , we were able to monetize the value of the contract while retaining the work we were performing and maintain our access to the contract for future potential work . tax cuts and jobs act public law no . story_separator_special_tag these costs will generally increase or decrease in conjunction with our level of products sold or contract work performed . costs and operating expenses also include expense for amortization of intangible assets acquired through our acquisitions . expense for amortization of acquisition related intangible assets is included in the segment results in which the acquisition is included . segment results also include expense for an allocation of corporate management costs . our costs and operating expenses decreased by approximately $ 61 million or 9 % in 2018 as compared to 2017. the change in costs and operating expenses resulted primarily from a decrease in our federal services group of approximately $ 74 million , an increase in our supply chain management group of approximately $ 3 million , and an increase in our aviation group of approximately $ 9 million . costs and expenses for 2018 included approximately $ 569 thousand associated with our acquisition of 1st choice aerospace in january 2019. our costs and operating expenses increased by approximately $ 66 million or 10 % in 2017 as compared to 2016. the change in costs and operating expenses resulted primarily from an increase in our federal services group of approximately $ 52 million , an increase in our supply chain management group of approximately $ 10 million , and an increase in our aviation group of approximately $ 4 million . our operating income for 2018 was relatively unchanged as compared to 2017 . operating group results included operating income increases for our federal services group of approximately $ 2.4 million and for our aviation group of approximately $ 1.4 million , and an operating income decrease for our supply chain management group of approximately $ 3.1 million . operating income for 2018 was decreased by approximately $ 569 thousand due to the costs and expenses associated with our acquisition of 1st choice aerospace in january 2019. our operating income increased by approximately $ 2.8 million or 5 % in 2017 as compared to 2016 . the change in operating income resulted primarily from changes in our operating group results and settlement of two material lawsuits . operating group results included an operating income increases for our federal services group of approximately $ 5.6 million and an operating income decreases for our aviation group of approximately $ 3.1 million and for our supply chain management group of approximately $ 878 thousand . our increase in revenue allowed us to allocate our corporate infrastructure costs over a larger revenue base , which benefited each operating group 's income . the combined effect of the lawsuit settlements resulted in a decrease in operating income of approximately $ 1.9 million for 2016. interest expense decreased approximately $ 258 thousand in 2018 as compared to 2017 and approximately $ 615 thousand in 2017 as compared to 2016 , primarily due to declines of our bank debt levels . interest expense also includes interest related to our executive and administrative headquarters facility lease . the amount of interest expense associated with our headquarters financing lease is approximately $ 1.4 million , $ 1.5 million and $ 1.6 million for 2018 , 2017 and 2016 , respectively . provision for income taxes our effective tax rate was 22.5 % for 2018 , 13.3 % for 2017 , and 35.7 % for 2016 . the tax act passed in december 2017 resulted in a decrease to our federal tax rate for 2018 to 21 % and lowered our cash tax payments for 2018. due to the tax act , we - 22 - recorded a one-time reduction in our deferred tax liabilities in the fourth quarter of 2017 that resulted in a reduction in our provision for income taxes of approximately $ 10.6 million for the year and lowered our effective tax rate for 2017. our tax rate is also affected by discrete items that may occur in any given year , but may not be consistent from year to year . in addition to state income taxes , certain tax credits and other items caused differences between our statutory u.s. federal income tax rate and our effective tax rate . other permanent differences and federal and state tax credits such as the work opportunity tax credit and a state educational improvement tax credit provided benefit to our tax rates for 2018 , 2017 and 2016 . supply chain management group results the results of operations for our supply chain management group are ( in thousands ) : replace_table_token_10_th revenues for our supply chain management group were substantially unchanged for 2018 , as compared to the prior year . revenues from sales to the usps declined approximately $ 4.9 million and revenues from sales to dod and commercial customers increased approximately $ 5.3 million or 16 % . costs and operating expenses for our supply chain management group increased approximately $ 3.4 million or 2 % and operating income decreased by approximately $ 3.1 million or 9 % for 2018 as compared to the prior year . the decrease in operating income was primarily attributable to market competition and a change in the mix of products sold . the products sold associated with our increasing dod and commercial customer revenues tend to lower our overall profit margins as our revenue mix changes . revenues for our supply chain management group increased approximately $ 9 million or 4 % for 2017 , as compared to the prior year . the revenue increase resulted primarily from an increase in sales to dod and commercial customers of approximately $ 9.6 million or 40 % . costs and operating expenses for our supply chain management group increased approximately $ 10 million or 6 % and operating income decreased by approximately $ 878 thousand or 3 % for 2017 as compared to the prior year . the increase in costs and operating expenses resulted primarily from an increase in products sold . - 23 - aviation group results the results of

