AMP Bank's performance was one of the bright spots in AMP's 2011 financial report, which was released yesterday.The bank, which has 100,000 customers, contributed A$61 million to group operating earnings in the year to December - up 45 per cent on the previous year.The net interest margin increased from 1.38 per cent in 2010 to 1.54 per cent last year.The mortgage book grew 10 percent to $11.2 billion. Growth was almost twice the system rate of growth.The deposit book grew 50 per cent to $7.2 billion. Retail deposits increased by $976 million, but the real growth came from demand for term deposits from superannuation fund members. Super TDs were up $1.4 billion.The bank completed a $920 mortgage securitisation last May.