39 annual report 2010 duke realty corporation | | related party transactions we provide property and asset management , leasing , construction and other tenant related services to unconsolidated companies in which we have equity interests . for the years ended december 31 , 2010 , 2009 and 2008 , respectively , we earned management fees of $ 7.6 million , $ 8.4 million and $ 7.8 million , leasing fees of $ 2.7 million , $ 4.2 million and $ 2.8 million and construction and development fees of $ 10.3 million , $ 10.2 million and $ 12.7 million from these companies . we recorded these fees based on contractual terms that approximate market rates for these types of services , and we have eliminated our ownership percentages of these fees in the consolidated financial statements . commitments and contingencies we have guaranteed the repayment of $ 95.4 million of economic development bonds issued by various municipalities in connection with certain commercial developments . we will be required to make payments under our guarantees to the extent that incremental taxes from specified developments are not sufficient to pay the bond debt service . management does not believe that it is probable that we will be required to make any significant payments in satisfaction of these guarantees . we also have guaranteed the repayment of secured and unsecured loans of six of our unconsolidated subsidiaries . at december 31 , 2010 , the maximum guarantee exposure for these loans was approximately $ 245.4 million . with the exception of the guarantee of the debt of 3630 peachtree joint venture , for which we recorded a contingent liability in 2009 of $ 36.3 million , management believes it probable that we will not be required to satisfy these guarantees . we lease certain land positions with terms extending to december 2080 , with a total obligation of $ 103.6 million . no payments on these ground leases are material in any individual year . we are subject to various legal proceedings and claims that arise in the ordinary course of business . in the opinion of management , the amount of any ultimate liability with respect to these actions will not materially affect our consolidated financial statements or results of operations . contractual obligations at december 31 , 2010 , we were subject to certain contractual payment obligations as described in the table below: .
what is the total long-term debt as a percentage of total contractual obligations?
( 1 ) our long-term debt consists of both secured and unsecured debt and includes both principal and interest . interest expense for variable rate debt was calculated using the interest rates as of december 31 , 2010 . ( 2 ) our unsecured lines of credit consist of an operating line of credit that matures february 2013 and the line of credit of a consolidated subsidiary that matures july 2011 . interest expense for our unsecured lines of credit was calculated using the most recent stated interest rates that were in effect . ( 3 ) our share of unconsolidated joint venture debt includes both principal and interest . interest expense for variable rate debt was calculated using the interest rate at december 31 , 2010 . ( 4 ) represents estimated remaining costs on the completion of owned development projects and third-party construction projects. .