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.

Text: 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: . <table class='wikitable'><tr><td>1</td><td>contractual obligations</td><td>payments due by period ( in thousands ) total</td><td>payments due by period ( in thousands ) 2011</td><td>payments due by period ( in thousands ) 2012</td><td>payments due by period ( in thousands ) 2013</td><td>payments due by period ( in thousands ) 2014</td><td>payments due by period ( in thousands ) 2015</td><td>payments due by period ( in thousands ) thereafter</td></tr><tr><td>2</td><td>long-term debt ( 1 )</td><td>$ 5413606</td><td>$ 629781</td><td>$ 548966</td><td>$ 725060</td><td>$ 498912</td><td>$ 473417</td><td>$ 2537470</td></tr><tr><td>3</td><td>lines of credit ( 2 )</td><td>214225</td><td>28046</td><td>9604</td><td>176575</td><td>-</td><td>-</td><td>-</td></tr><tr><td>4</td><td>share of debt of unconsolidated joint ventures ( 3 )</td><td>447573</td><td>87602</td><td>27169</td><td>93663</td><td>34854</td><td>65847</td><td>138438</td></tr><tr><td>5</td><td>ground leases</td><td>103563</td><td>2199</td><td>2198</td><td>2169</td><td>2192</td><td>2202</td><td>92603</td></tr><tr><td>6</td><td>operating leases</td><td>2704</td><td>840</td><td>419</td><td>395</td><td>380</td><td>370</td><td>300</td></tr><tr><td>7</td><td>development and construction backlog costs ( 4 )</td><td>521041</td><td>476314</td><td>44727</td><td>-</td><td>-</td><td>-</td><td>-</td></tr><tr><td>8</td><td>other</td><td>1967</td><td>1015</td><td>398</td><td>229</td><td>90</td><td>54</td><td>181</td></tr><tr><td>9</td><td>total contractual obligations</td><td>$ 6704679</td><td>$ 1225797</td><td>$ 633481</td><td>$ 998091</td><td>$ 536428</td><td>$ 541890</td><td>$ 2768992</td></tr></table> ( 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. .
Question: what is the total long-term debt?
Answer: 5413606.0
Question: what are the total contractual obligations?
Answer: 6704679.0
Question: what fraction of total contractual obligations is long-term debt?
Answer: 0.80744
Question: what percentage does this represent?

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