2022 asset utilization 2013 in response to economic conditions and lower revenue in 2009 , we implemented productivity initiatives to improve efficiency and reduce costs , in addition to adjusting our resources to reflect lower demand . although varying throughout the year , our resource reductions included removing from service approximately 26% ( 26 % ) of our road locomotives and 18% ( 18 % ) of our freight car inventory by year end . we also reduced shift levels at most rail facilities and closed or significantly reduced operations in 30 of our 114 principal rail yards . these demand-driven resource adjustments and our productivity initiatives combined to reduce our workforce by 10% ( 10 % ) . 2022 fuel prices 2013 as the economy worsened during the third and fourth quarters of 2008 , fuel prices dropped dramatically , reaching $ 33.87 per barrel in december 2008 , a near five-year low . throughout 2009 , crude oil prices generally increased , ending the year around $ 80 per barrel . overall , our average fuel price decreased by 44% ( 44 % ) in 2009 , reducing operating expenses by $ 1.3 billion compared to 2008 . we also reduced our consumption rate by 4% ( 4 % ) during the year , saving approximately 40 million gallons of fuel . the use of newer , more fuel efficient locomotives ; increased use of distributed locomotive power ; fuel conservation programs ; and improved network operations and asset utilization all contributed to this improvement . 2022 free cash flow 2013 cash generated by operating activities totaled $ 3.2 billion , yielding free cash flow of $ 515 million in 2009 . free cash flow is defined as cash provided by operating activities , less cash used in investing activities and dividends paid . free cash flow is not considered a financial measure under accounting principles generally accepted in the united states ( gaap ) by sec regulation g and item 10 of sec regulation s-k . we believe free cash flow is important in evaluating our financial performance and measures our ability to generate cash without additional external financings . free cash flow should be considered in addition to , rather than as a substitute for , cash provided by operating activities . the following table reconciles cash provided by operating activities ( gaap measure ) to free cash flow ( non-gaap measure ) : millions of dollars 2009 2008 2007 .
what was the percentage change in free cash flow from 2007 to 2008?
2010 outlook 2022 safety 2013 operating a safe railroad benefits our employees , our customers , our shareholders , and the public . we will continue using a multi-faceted approach to safety , utilizing technology , risk assessment , quality control , and training , and by engaging our employees . we will continue implementing total safety culture ( tsc ) throughout our operations . tsc is designed to establish , maintain , reinforce , and promote safe practices among co-workers . this process allows us to identify and implement best practices for employee and operational safety . reducing grade-crossing incidents is a critical aspect of our safety programs , and we will continue our efforts to maintain , upgrade , and close crossings ; install video cameras on locomotives ; and educate the public about crossing safety through our own programs , various industry programs , and other activities . 2022 transportation plan 2013 to build upon our success in recent years , we will continue evaluating traffic flows and network logistic patterns , which can be quite dynamic from year-to-year , to identify additional opportunities to simplify operations , remove network variability and improve network efficiency and asset utilization . we plan to adjust manpower and our locomotive and rail car fleets to .