Financial report context:
notes to consolidated financial statements certain of aon 2019s european subsidiaries have a a650 million ( u.s . $ 942 million ) multi-currency revolving loan credit facility . this facility will mature in october 2010 , unless aon opts to extend the facility . commitment fees of 8.75 basis points are payable on the unused portion of the facility . at december 31 , 2007 , aon has borrowed a376 million and $ 250 million ( $ 795 million ) under this facility . at december 31 , 2006 , a307 million was borrowed . at december 31 , 2007 , $ 250 million of the euro facility is classified as short-term debt in the consolidated statements of financial position . aon has guaranteed the obligations of its subsidiaries with respect to this facility . aon maintains a $ 600 million , 5-year u.s . committed bank credit facility to support commercial paper and other short-term borrowings , which expires in february 2010 . this facility permits the issuance of up to $ 150 million in letters of credit . at december 31 , 2007 and 2006 , aon had $ 20 million in letters of credit outstanding . based on aon 2019s current credit ratings , commitment fees of 10 basis points are payable on the unused portion of the facility . for both the u.s . and euro facilities , aon is required to maintain consolidated net worth , as defined , of at least $ 2.5 billion , a ratio of consolidated ebitda ( earnings before interest , taxes , depreciation and amortization ) to consolidated interest expense of 4 to 1 and a ratio of consolidated debt to ebitda of not greater than 3 to 1 . aon also has other foreign facilities available , which include a a337.5 million ( $ 74 million ) facility , a a25 million ( $ 36 million ) facility , and a a20 million ( $ 29 million ) facility . outstanding debt securities , including aon capital a 2019s , are not redeemable by aon prior to maturity . there are no sinking fund provisions . interest is payable semi-annually on most debt securities . repayments of long-term debt are $ 548 million , $ 382 million and $ 225 million in 2010 , 2011 and 2012 , respectively . other information related to aon 2019s debt is as follows: .

Financial table:
years ended december 31: interest paid ( millions ); 2007: $ 147; 2006: $ 130; 2005: $ 130
years ended december 31: weighted-average interest rates 2014 short-term borrowings; 2007: 5.1% ( 5.1 % ); 2006: 4.4% ( 4.4 % ); 2005: 3.5% ( 3.5 % )

Additional report context:
lease commitments aon has noncancelable operating leases for certain office space , equipment and automobiles . these leases expire at various dates and may contain renewal and expansion options . in addition to base rental costs , occupancy lease agreements generally provide for rent escalations resulting from increased assessments for real estate taxes and other charges . approximately 81% ( 81 % ) of aon 2019s lease obligations are for the use of office space . rental expense for operating leases amounted to $ 368 million , $ 350 million and $ 337 million for 2007 , 2006 and 2005 , respectively , after deducting rentals from subleases ( $ 40 million , $ 33 million and $ 29 million for 2007 , 2006 and 2005 , respectively ) . aon corporation .

Question: what percentage of the letter of credit remains available as of december 31 , 2007?
Answer: 86.7%