pre_text: volume declines in cement , some agricultural products , and newsprint shipments partially offset the increases . operating expenses millions of dollars 2008 2007 2006 % (  % ) change 2008 v 2007 % (  % ) change 2007 v 2006 .
post_text: operating expenses increased $ 987 million in 2008 . our fuel price per gallon rose 39% ( 39 % ) during the year , increasing operating expenses by $ 1.1 billion compared to 2007 . wage , benefit , and materials inflation , higher depreciation , and costs associated with the january cascade mudslide and hurricanes gustav and ike also increased expenses during the year . cost savings from productivity improvements , better resource utilization , and lower volume helped offset these increases . operating expenses increased $ 214 million in 2007 versus 2006 . higher fuel prices , which rose 9% ( 9 % ) during the period , increased operating expenses by $ 242 million . wage , benefit and materials inflation and higher depreciation expense also increased expenses during the year . productivity improvements , better resource utilization , and a lower fuel consumption rate helped offset these increases . compensation and benefits 2013 compensation and benefits include wages , payroll taxes , health and welfare costs , pension costs , other postretirement benefits , and incentive costs . productivity initiatives in all areas , combined with lower volume , led to a 4% ( 4 % ) decline in our workforce for 2008 , saving $ 227 million compared to 2007 . conversely , general wage and benefit inflation and higher pension and postretirement benefits increased expenses in 2008 , partially offsetting these reductions . operational improvements and lower volume levels in 2007 led to a 1% ( 1 % ) decline in our workforce , saving $ 79 million in 2007 compared to 2006 . a smaller workforce and less need for new train personnel reduced training costs during the year , which contributed to the improvement . general wage and benefit inflation mostly offset the reductions , reflecting higher salaries and wages and the impact of higher healthcare and other benefit costs . fuel 2013 fuel includes locomotive fuel and gasoline for highway and non-highway vehicles and heavy equipment . diesel fuel prices , which averaged $ 3.15 per gallon ( including taxes and transportation costs ) in 2008 compared to $ 2.27 per gallon in 2007 , increased expenses by $ 1.1 billion . a 4% ( 4 % ) improvement in our fuel consumption rate resulted in $ 136 million of cost savings due to the use of newer , more fuel 2008 operating expenses .
table: <i>Millions of Dollars</i> <i>2008</i> <i>2007</i> <i>2006</i> <i>% Change 2008 v 2007</i> % Change 2007 v 2006
table: Compensation and benefits $4,457 $4,526 $4,535 (2)% -%
table: Fuel 3,983 3,104 2,968 28 5
table: Purchased services and materials 1,902 1,856 1,756 2 6
table: Depreciation 1,387 1,321 1,237 5 7
table: Equipment and other rents 1,326 1,368 1,396 (3) (2)
table: Other 840 733 802 15 (9)
table: Total $13,895 $12,908 $12,694 8 % 2%
question: Analyse this data from a financial earnings document. what percent of total operating expenses was fuel in 2008?