debt maturities 2013 the following table presents aggregate debt maturities as of december 31 , 2008 , excluding market value adjustments . millions of dollars .
what percentage of total aggregate debt maturities as of december 31 , 2008 are due after 2013?
as of december 31 , 2008 , we have reclassified as long-term debt approximately $ 400 million of debt due within one year that we intend to refinance . this reclassification reflects our ability and intent to refinance any short-term borrowings and certain current maturities of long-term debt on a long-term basis . at december 31 , 2007 , we reclassified as long-term debt approximately $ 550 million of debt due within one year that we intended to refinance at that time . mortgaged properties 2013 equipment with a carrying value of approximately $ 2.7 billion and $ 2.8 billion at december 31 , 2008 and 2007 , respectively , serves as collateral for capital leases and other types of equipment obligations in accordance with the secured financing arrangements utilized to acquire such railroad equipment . as a result of the merger of missouri pacific railroad company ( mprr ) with and into uprr on january 1 , 1997 , and pursuant to the underlying indentures for the mprr mortgage bonds , uprr must maintain the same value of assets after the merger in order to comply with the security requirements of the mortgage bonds . as of the merger date , the value of the mprr assets that secured the mortgage bonds was approximately $ 6.0 billion . in accordance with the terms of the indentures , this collateral value must be maintained during the entire term of the mortgage bonds irrespective of the outstanding balance of such bonds . credit facilities 2013 on december 31 , 2008 , we had $ 1.9 billion of credit available under our revolving credit facility ( the facility ) . the facility is designated for general corporate purposes and supports the issuance of commercial paper . we did not draw on the facility during 2008 . commitment fees and interest rates payable under the facility are similar to fees and rates available to comparably rated , investment- grade borrowers . the facility allows borrowings at floating rates based on london interbank offered rates , plus a spread , depending upon our senior unsecured debt ratings . the facility requires union pacific corporation to maintain a debt-to-net-worth coverage ratio as a condition to making a borrowing . at december 31 , 2008 , and december 31 , 2007 ( and at all times during these periods ) , we were in compliance with this covenant . the definition of debt used for purposes of calculating the debt-to-net-worth coverage ratio includes , among other things , certain credit arrangements , capital leases , guarantees and unfunded and vested pension benefits under title iv of erisa . at december 31 , 2008 , the debt-to-net-worth coverage ratio allowed us to carry up to $ 30.9 billion of debt ( as defined in the facility ) , and we had $ 9.9 billion of debt ( as defined in the facility ) outstanding at that date . under our current capital plans , we expect to continue to satisfy the debt-to-net-worth coverage ratio ; however , many factors beyond our reasonable control ( including the risk factors in item 1a of this report ) could affect our ability to comply with this provision in the future . the facility does not include any other financial restrictions , credit rating triggers ( other than rating-dependent pricing ) , or any other provision that could require us to post collateral . the .