notes to consolidated financial statements sumitomo mitsui financial group , inc . ( smfg ) provides the firm with credit loss protection on certain approved loan commitments ( primarily investment-grade commercial lending commitments ) . the notional amount of such loan commitments was $ 29.24 billion and $ 32.41 billion as of december 2013 and december 2012 , respectively . the credit loss protection on loan commitments provided by smfg is generally limited to 95% ( 95 % ) of the first loss the firm realizes on such commitments , up to a maximum of approximately $ 950 million . in addition , subject to the satisfaction of certain conditions , upon the firm 2019s request , smfg will provide protection for 70% ( 70 % ) of additional losses on such commitments , up to a maximum of $ 1.13 billion , of which $ 870 million and $ 300 million of protection had been provided as of december 2013 and december 2012 , respectively . the firm also uses other financial instruments to mitigate credit risks related to certain commitments not covered by smfg . these instruments primarily include credit default swaps that reference the same or similar underlying instrument or entity , or credit default swaps that reference a market index . warehouse financing . the firm provides financing to clients who warehouse financial assets . these arrangements are secured by the warehoused assets , primarily consisting of corporate loans and commercial mortgage loans . contingent and forward starting resale and securities borrowing agreements/forward starting repurchase and secured lending agreements the firm enters into resale and securities borrowing agreements and repurchase and secured lending agreements that settle at a future date , generally within three business days . the firm also enters into commitments to provide contingent financing to its clients and counterparties through resale agreements . the firm 2019s funding of these commitments depends on the satisfaction of all contractual conditions to the resale agreement and these commitments can expire unused . investment commitments the firm 2019s investment commitments consist of commitments to invest in private equity , real estate and other assets directly and through funds that the firm raises and manages . these commitments include $ 659 million and $ 872 million as of december 2013 and december 2012 , respectively , related to real estate private investments and $ 6.46 billion and $ 6.47 billion as of december 2013 and december 2012 , respectively , related to corporate and other private investments . of these amounts , $ 5.48 billion and $ 6.21 billion as of december 2013 and december 2012 , respectively , relate to commitments to invest in funds managed by the firm . if these commitments are called , they would be funded at market value on the date of investment . leases the firm has contractual obligations under long-term noncancelable lease agreements , principally for office space , expiring on various dates through 2069 . certain agreements are subject to periodic escalation provisions for increases in real estate taxes and other charges . the table below presents future minimum rental payments , net of minimum sublease rentals . in millions december 2013 .
what percentage of future minimum rental payments are due in 2015?
rent charged to operating expense was $ 324 million for 2013 , $ 374 million for 2012 and $ 475 million for 2011 . operating leases include office space held in excess of current requirements . rent expense relating to space held for growth is included in 201coccupancy . 201d the firm records a liability , based on the fair value of the remaining lease rentals reduced by any potential or existing sublease rentals , for leases where the firm has ceased using the space and management has concluded that the firm will not derive any future economic benefits . costs to terminate a lease before the end of its term are recognized and measured at fair value on termination . contingencies legal proceedings . see note 27 for information about legal proceedings , including certain mortgage-related matters . certain mortgage-related contingencies . there are multiple areas of focus by regulators , governmental agencies and others within the mortgage market that may impact originators , issuers , servicers and investors . there remains significant uncertainty surrounding the nature and extent of any potential exposure for participants in this market . 182 goldman sachs 2013 annual report .