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: .
[['years ended december 31', '2007', '2006', '2005'], ['interest paid ( millions )', '$ 147', '$ 130', '$ 130'], ['weighted-average interest rates 2014 short-term borrowings', '5.1% ( 5.1 % )', '4.4% ( 4.4 % )', '3.5% ( 3.5 % )']]
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%