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.


from time to time , we may elect to use foreign currency forward contracts to reduce the risk from exchange rate fluctuations on intercompany transactions and projected inventory purchases for our european and canadian subsidiaries . in addition , we may elect to enter into foreign currency forward contracts to reduce the risk associated with foreign currency exchange rate fluctuations on pound sterling denominated balance sheet items . we do not enter into derivative financial instruments for speculative or trading purposes . based on the foreign currency forward contracts outstanding as of december 31 , 2011 , we receive u.s . dollars in exchange for canadian dollars at a weighted average contractual forward foreign currency exchange rate of 1.03 cad per $ 1.00 , u.s . dollars in exchange for euros at a weighted average contractual foreign currency exchange rate of 20ac0.77 per $ 1.00 and euros in exchange for pounds sterling at a weighted average contractual foreign currency exchange rate of a30.84 per 20ac1.00 . as of december 31 , 2011 , the notional value of our outstanding foreign currency forward contracts for our canadian subsidiary was $ 51.1 million with contract maturities of 1 month or less , and the notional value of our outstanding foreign currency forward contracts for our european subsidiary was $ 50.0 million with contract maturities of 1 month . as of december 31 , 2011 , the notional value of our outstanding foreign currency forward contract used to mitigate the foreign currency exchange rate fluctuations on pound sterling denominated balance sheet items was 20ac10.5 million , or $ 13.6 million , with a contract maturity of 1 month . the foreign currency forward contracts are not designated as cash flow hedges , and accordingly , changes in their fair value are recorded in other expense , net on the consolidated statements of income . the fair values of our foreign currency forward contracts were liabilities of $ 0.7 million and $ 0.6 million as of december 31 , 2011 and 2010 , respectively , and were included in accrued expenses on the consolidated balance sheet . refer to note 10 to the consolidated financial statements for a discussion of the fair value measurements . included in other expense , net were the following amounts related to changes in foreign currency exchange rates and derivative foreign currency forward contracts: . <table class='wikitable'><tr><td>1</td><td>year ended december 31 , ( in thousands )</td><td>year ended december 31 , 2011</td><td>year ended december 31 , 2010</td><td>2009</td></tr><tr><td>2</td><td>unrealized foreign currency exchange rate gains ( losses )</td><td>$ -4027 ( 4027 )</td><td>$ -1280 ( 1280 )</td><td>$ 5222</td></tr><tr><td>3</td><td>realized foreign currency exchange rate gains ( losses )</td><td>298</td><td>-2638 ( 2638 )</td><td>-261 ( 261 )</td></tr><tr><td>4</td><td>unrealized derivative losses</td><td>-31 ( 31 )</td><td>-809 ( 809 )</td><td>-1060 ( 1060 )</td></tr><tr><td>5</td><td>realized derivative gains ( losses )</td><td>1696</td><td>3549</td><td>-4412 ( 4412 )</td></tr></table> we enter into foreign currency forward contracts with major financial institutions with investment grade credit ratings and are exposed to credit losses in the event of non-performance by these financial institutions . this credit risk is generally limited to the unrealized gains in the foreign currency forward contracts . however , we monitor the credit quality of these financial institutions and consider the risk of counterparty default to be minimal . although we have entered into foreign currency forward contracts to minimize some of the impact of foreign currency exchange rate fluctuations on future cash flows , we cannot be assured that foreign currency exchange rate fluctuations will not have a material adverse impact on our financial condition and results of operations . inflation inflationary factors such as increases in the cost of our product and overhead costs may adversely affect our operating results . although we do not believe that inflation has had a material impact on our financial position or results of operations to date , a high rate of inflation in the future may have an adverse effect on our ability to maintain current levels of gross margin and selling , general and administrative expenses as a percentage of net revenues if the selling prices of our products do not increase with these increased costs. .
Question: what is the change in the balance of foreign currency forward contracts liability from 2010 to 2011?

0.1