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: .

Payments due by Period (in thousands)
Contractual Obligations
Total
2011
2012
2013
2014
2015
Thereafter
Long-term debt (1)
$5,413,606
$629,781
$548,966
$725,060
$498,912
$473,417
$2,537,470
Lines of credit (2)
214,225
28,046
9,604
176,575
-
-
-
Share of debt of unconsolidated joint ventures (3)
447,573
87,602
27,169
93,663
34,854
65,847
138,438
Ground leases
103,563
2,199
2,198
2,169
2,192
2,202
92,603
Operating leases
2,704
840
419
395
380
370
300
Development and construction backlog costs (4)
521,041
476,314
44,727
-
-
-
-
Other
1,967
1,015
398
229
90
54
181
Total Contractual Obligations
$6,704,679
$1,225,797
$633,481
$998,091
$536,428
$541,890
$2,768,992

( 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: Analyse this data from a financial earnings document. what is the total long-term debt as a percentage of total contractual obligations?
Choices:
3629649046247400
6.298
0.8074
-80.7437
80.7437
Correct choice index: 4