nearly all of the remaining increase in fuel expense , reflecting a relatively flat year-over-year fuel consumption rate . f0b7 free cash flow 2013 cash generated by operating activities totaled $ 5.9 billion , yielding record free cash flow of $ 1.9 billion in 2011 . free cash flow is defined as cash provided by operating activities ( adjusted for the reclassification of our receivables securitization facility ) , less cash used in investing activities and dividends paid