IndyMac reported that during April 2008, Moody's and Standard & Poor's downgraded the ratings on a significant number of Mortgage-backed security (MBS) bonds including $160 million of those issued by IndyMac and which the bank retained in its MBS portfolio. If IndyMac's downgraded MBS bond ratings had been in effect at March 31, 2008, what would the bank's capital ratio have been