Financial report context:
amount of commitment expiration per period other commercial commitments after millions of dollars total 2010 2011 2012 2013 2014 2014 .

Financial table:
other commercial commitmentsmillions of dollars: credit facilities [a]; total: $ 1900; amount of commitment expiration per period 2010: $ -; amount of commitment expiration per period 2011: $ -; amount of commitment expiration per period 2012: $ 1900; amount of commitment expiration per period 2013: $ -; amount of commitment expiration per period 2014: $ -; amount of commitment expiration per period after 2014: $ -
other commercial commitmentsmillions of dollars: sale of receivables [b]; total: 600; amount of commitment expiration per period 2010: 600; amount of commitment expiration per period 2011: -; amount of commitment expiration per period 2012: -; amount of commitment expiration per period 2013: -; amount of commitment expiration per period 2014: -; amount of commitment expiration per period after 2014: -
other commercial commitmentsmillions of dollars: guarantees [c]; total: 416; amount of commitment expiration per period 2010: 29; amount of commitment expiration per period 2011: 76; amount of commitment expiration per period 2012: 24; amount of commitment expiration per period 2013: 8; amount of commitment expiration per period 2014: 214; amount of commitment expiration per period after 2014: 65
other commercial commitmentsmillions of dollars: standby letters of credit [d]; total: 22; amount of commitment expiration per period 2010: 22; amount of commitment expiration per period 2011: -; amount of commitment expiration per period 2012: -; amount of commitment expiration per period 2013: -; amount of commitment expiration per period 2014: -; amount of commitment expiration per period after 2014: -
other commercial commitmentsmillions of dollars: total commercial commitments; total: $ 2938; amount of commitment expiration per period 2010: $ 651; amount of commitment expiration per period 2011: $ 76; amount of commitment expiration per period 2012: $ 1924; amount of commitment expiration per period 2013: $ 8; amount of commitment expiration per period 2014: $ 214; amount of commitment expiration per period after 2014: $ 65

Additional report context:
[a] none of the credit facility was used as of december 31 , 2009 . [b] $ 400 million of the sale of receivables program was utilized at december 31 , 2009 . [c] includes guaranteed obligations related to our headquarters building , equipment financings , and affiliated operations . [d] none of the letters of credit were drawn upon as of december 31 , 2009 . off-balance sheet arrangements sale of receivables 2013 the railroad transfers most of its accounts receivable to union pacific receivables , inc . ( upri ) , a bankruptcy-remote subsidiary , as part of a sale of receivables facility . upri sells , without recourse on a 364-day revolving basis , an undivided interest in such accounts receivable to investors . the total capacity to sell undivided interests to investors under the facility was $ 600 million and $ 700 million at december 31 , 2009 and 2008 , respectively . the value of the outstanding undivided interest held by investors under the facility was $ 400 million and $ 584 million at december 31 , 2009 and 2008 , respectively . during 2009 , upri reduced the outstanding undivided interest held by investors due to a decrease in available receivables . the value of the undivided interest held by investors is not included in our consolidated financial statements . the value of the undivided interest held by investors was supported by $ 817 million and $ 1015 million of accounts receivable held by upri at december 31 , 2009 and 2008 , respectively . at december 31 , 2009 and 2008 , the value of the interest retained by upri was $ 417 million and $ 431 million , respectively . this retained interest is included in accounts receivable in our consolidated financial statements . the interest sold to investors is sold at carrying value , which approximates fair value , and there is no gain or loss recognized from the transaction . the value of the outstanding undivided interest held by investors could fluctuate based upon the availability of eligible receivables and is directly affected by changing business volumes and credit risks , including default and dilution . if default or dilution ratios increase one percent , the value of the outstanding undivided interest held by investors would not change as of december 31 , 2009 . should our credit rating fall below investment grade , the value of the outstanding undivided interest held by investors would be reduced , and , in certain cases , the investors would have the right to discontinue the facility . the railroad services the sold receivables ; however , the railroad does not recognize any servicing asset or liability , as the servicing fees adequately compensate us for these responsibilities . the railroad collected approximately $ 13.8 billion and $ 17.8 billion during the years ended december 31 , 2009 and 2008 , respectively . upri used certain of these proceeds to purchase new receivables under the facility . the costs of the sale of receivables program are included in other income and were $ 9 million , $ 23 million , and $ 35 million for 2009 , 2008 , and 2007 , respectively . the costs include interest , which will vary based on prevailing commercial paper rates , program fees paid to banks , commercial paper issuing costs , and fees for unused commitment availability . the decrease in the 2009 costs was primarily attributable to lower commercial paper rates and a decrease in the outstanding interest held by investors. .

Question: what percentage of total commercial commitments are sale of receivables?
Answer: 20%