Read the following texts and table with financial data from an S&P 500 earnings report carefully.Based on the question-answer history (if provided), answer the last question. The answer may require mathematical calculation based on the data provided.


construction of cvn-79 john f . kennedy , construction of the u.s . coast guard 2019s fifth national security cutter ( unnamed ) , advance planning efforts for the cvn-72 uss abraham lincoln rcoh , and continued execution of the cvn-71 uss theodore roosevelt rcoh . 2010 2014the value of new contract awards during the year ended december 31 , 2010 , was approximately $ 3.6 billion . significant new awards during this period included $ 480 million for the construction of the u.s . coast guard 2019s fourth national security cutter hamilton , $ 480 million for design and long-lead material procurement activities for the cvn-79 john f . kennedy aircraft carrier , $ 377 million for cvn-78 gerald r . ford , $ 224 million for lha-7 ( unnamed ) , $ 184 million for lpd-26 john p . murtha , $ 114 million for ddg-114 ralph johnson and $ 62 million for long-lead material procurement activities for lpd-27 ( unnamed ) . liquidity and capital resources we endeavor to ensure the most efficient conversion of operating results into cash for deployment in operating our businesses and maximizing stockholder value . we use various financial measures to assist in capital deployment decision making , including net cash provided by operating activities and free cash flow . we believe these measures are useful to investors in assessing our financial performance . the table below summarizes key components of cash flow provided by ( used in ) operating activities: . <table class='wikitable'><tr><td>1</td><td>( $ in millions )</td><td>year ended december 31 2011</td><td>year ended december 31 2010</td><td>year ended december 31 2009</td></tr><tr><td>2</td><td>net earnings ( loss )</td><td>$ -94 ( 94 )</td><td>$ 135</td><td>$ 124</td></tr><tr><td>3</td><td>goodwill impairment</td><td>290</td><td>0</td><td>0</td></tr><tr><td>4</td><td>deferred income taxes</td><td>27</td><td>-19 ( 19 )</td><td>-98 ( 98 )</td></tr><tr><td>5</td><td>depreciation and amortization</td><td>190</td><td>183</td><td>186</td></tr><tr><td>6</td><td>stock-based compensation</td><td>42</td><td>0</td><td>0</td></tr><tr><td>7</td><td>retiree benefit funding less than ( in excess of ) expense</td><td>122</td><td>33</td><td>-28 ( 28 )</td></tr><tr><td>8</td><td>trade working capital decrease ( increase )</td><td>-49 ( 49 )</td><td>27</td><td>-272 ( 272 )</td></tr><tr><td>9</td><td>net cash provided by ( used in ) operating activities</td><td>$ 528</td><td>$ 359</td><td>$ -88 ( 88 )</td></tr></table> cash flows we discuss below our major operating , investing and financing activities for each of the three years in the period ended december 31 , 2011 , as classified on our consolidated statements of cash flows . operating activities 2011 2014cash provided by operating activities was $ 528 million in 2011 compared with $ 359 million in 2010 . the increase of $ 169 million was due principally to increased earnings net of impairment charges and lower pension contributions , offset by an increase in trade working capital . net cash paid by northrop grumman on our behalf for u.s . federal income tax obligations was $ 53 million . we expect cash generated from operations for 2012 to be sufficient to service debt , meet contract obligations , and finance capital expenditures . although 2012 cash from operations is expected to be sufficient to service these obligations , we may from time to time borrow funds under our credit facility to accommodate timing differences in cash flows . 2010 2014net cash provided by operating activities was $ 359 million in 2010 compared with cash used of $ 88 million in 2009 . the change of $ 447 million was due principally to a decrease in discretionary pension contributions of $ 97 million , a decrease in trade working capital of $ 299 million , and a decrease in deferred income taxes of $ 79 million . in 2009 , trade working capital balances included the unfavorable impact of delayed customer billings associated with the negative performance adjustments on the lpd-22 through lpd-25 contract due to projected cost increases at completion . see note 7 : contract charges in item 8 . the change in deferred taxes was due principally to the timing of contract related deductions . u.s . federal income tax payments made by northrop grumman on our behalf were $ 89 million in 2010. .
Question: what is the net cash flow by operating activities in 2010?
Answer: 359.0
Question: what about in 2009?

-88.0