the goldman sachs group , inc . and subsidiaries notes to consolidated financial statements long-term debt instruments the aggregate contractual principal amount of long-term other secured financings for which the fair value option was elected exceeded the related fair value by $ 361 million and $ 362 million as of december 2016 and december 2015 , respectively . the aggregate contractual principal amount of unsecured long-term borrowings for which the fair value option was elected exceeded the related fair value by $ 1.56 billion and $ 1.12 billion as of december 2016 and december 2015 , respectively . the amounts above include both principal- and non-principal-protected long-term borrowings . impact of credit spreads on loans and lending commitments the estimated net gain attributable to changes in instrument-specific credit spreads on loans and lending commitments for which the fair value option was elected was $ 281 million for 2016 , $ 751 million for 2015 and $ 1.83 billion for 2014 , respectively . the firm generally calculates the fair value of loans and lending commitments for which the fair value option is elected by discounting future cash flows at a rate which incorporates the instrument-specific credit spreads . for floating-rate loans and lending commitments , substantially all changes in fair value are attributable to changes in instrument-specific credit spreads , whereas for fixed-rate loans and lending commitments , changes in fair value are also attributable to changes in interest rates . debt valuation adjustment the firm calculates the fair value of financial liabilities for which the fair value option is elected by discounting future cash flows at a rate which incorporates the firm 2019s credit spreads . the net dva on such financial liabilities was a loss of $ 844 million ( $ 544 million , net of tax ) for 2016 and was included in 201cdebt valuation adjustment 201d in the consolidated statements of comprehensive income . the gains/ ( losses ) reclassified to earnings from accumulated other comprehensive loss upon extinguishment of such financial liabilities were not material for 2016 . note 9 . loans receivable loans receivable is comprised of loans held for investment that are accounted for at amortized cost net of allowance for loan losses . interest on loans receivable is recognized over the life of the loan and is recorded on an accrual basis . the table below presents details about loans receivable. .
what percentage of total loans receivable gross in 2015 were loans backed by commercial real estate?
as of december 2016 and december 2015 , the fair value of loans receivable was $ 49.80 billion and $ 45.19 billion , respectively . as of december 2016 , had these loans been carried at fair value and included in the fair value hierarchy , $ 28.40 billion and $ 21.40 billion would have been classified in level 2 and level 3 , respectively . as of december 2015 , had these loans been carried at fair value and included in the fair value hierarchy , $ 23.91 billion and $ 21.28 billion would have been classified in level 2 and level 3 , respectively . the firm also extends lending commitments that are held for investment and accounted for on an accrual basis . as of december 2016 and december 2015 , such lending commitments were $ 98.05 billion and $ 93.92 billion , respectively . substantially all of these commitments were extended to corporate borrowers and were primarily related to the firm 2019s relationship lending activities . the carrying value and the estimated fair value of such lending commitments were liabilities of $ 327 million and $ 2.55 billion , respectively , as of december 2016 , and $ 291 million and $ 3.32 billion , respectively , as of december 2015 . as of december 2016 , had these lending commitments been carried at fair value and included in the fair value hierarchy , $ 1.10 billion and $ 1.45 billion would have been classified in level 2 and level 3 , respectively . as of december 2015 , had these lending commitments been carried at fair value and included in the fair value hierarchy , $ 1.35 billion and $ 1.97 billion would have been classified in level 2 and level 3 , respectively . goldman sachs 2016 form 10-k 147 .