conduit assets by asset origin .
what is percentage change in total conduit asset from 2007 to 2008?
the conduits meet the definition of a vie , as defined by fin 46 ( r ) . we have determined that we are not the primary beneficiary of the conduits , as defined by fin 46 ( r ) , and do not record them in our consolidated financial statements . we hold no direct or indirect ownership interest in the conduits , but we provide subordinated financial support to them through contractual arrangements . standby letters of credit absorb certain actual credit losses from the conduit assets ; our commitment under these letters of credit totaled $ 1.00 billion and $ 1.04 billion at december 31 , 2008 and 2007 , respectively . liquidity asset purchase agreements provide liquidity to the conduits in the event they cannot place commercial paper in the ordinary course of their business ; these facilities , which require us to purchase assets from the conduits at par , would provide the needed liquidity to repay maturing commercial paper if there was a disruption in the asset-backed commercial paper market . the aggregate commitment under the liquidity asset purchase agreements was approximately $ 23.59 billion and $ 28.37 billion at december 31 , 2008 and 2007 , respectively . we did not accrue for any losses associated with either our commitment under the standby letters of credit or the liquidity asset purchase agreements in our consolidated statement of condition at december 31 , 2008 or 2007 . during the first quarter of 2008 , pursuant to the contractual terms of our liquidity asset purchase agreements with the conduits , we were required to purchase $ 850 million of conduit assets . the purchase was the result of various factors , including the continued illiquidity in the commercial paper markets . the securities were purchased at prices determined in accordance with existing contractual terms in the liquidity asset purchase agreements , and which exceeded their fair value . accordingly , during the first quarter of 2008 , the securities were written down to their fair value through a $ 12 million reduction of processing fees and other revenue in our consolidated statement of income , and are carried at fair value in securities available for sale in our consolidated statement of condition . none of our liquidity asset purchase agreements with the conduits were drawn upon during the remainder of 2008 , and no draw-downs on the standby letters of credit occurred during 2008 . the conduits generally sell commercial paper to independent third-party investors . however , we sometimes purchase commercial paper from the conduits . as of december 31 , 2008 , we held an aggregate of approximately $ 230 million of commercial paper issued by the conduits , and $ 2 million at december 31 , 2007 . in addition , approximately $ 5.70 billion of u.s . conduit-issued commercial paper had been sold to the cpff . the cpff is scheduled to expire on october 31 , 2009 . the weighted-average maturity of the conduits 2019 commercial paper in the aggregate was approximately 25 days as of december 31 , 2008 , compared to approximately 20 days as of december 31 , 2007 . each of the conduits has issued first-loss notes to independent third parties , which third parties absorb first- dollar losses related to credit risk . aggregate first-loss notes outstanding at december 31 , 2008 for the four conduits totaled $ 67 million , compared to $ 32 million at december 31 , 2007 . actual credit losses of the conduits .