National Australia Bank has achieved what Commonwealth Bank under Ralph Norris could not: it has climbed from the bottom of the retail customer satisfaction ratings to the top.The latest Roy Morgan Research consumer banking customer satisfaction report, published yesterday, puts NAB at the head of the Big Four with a rating of 77.5 per cent. ANZ, which has had the highest rating since 2004, has a rating of 77 per cent. Commonwealth Bank has a satisfaction rating of 76.3 per cent and Westpac 76.1 per cent.NAB fell to the bottom of its peer group rankings in mid-2008 and stayed there for two years.NAB, ANZ and Commonwealth Bank all improved their satisfaction ratings over the past three months, while Westpac's score fell 40 basis points.The overall rise in the big banks' ratings was in contrast to credit unions and foreign banks, whose scores fell. The gap between big bank satisfaction ratings and the rest of the market continues to narrow.The financial institution in the Roy Morgan sample with the most satisfied customers remains ME Bank, with a rating of 92.4 per cent. Greater Building Society has a rating of 91.2 per cent, Bendigo and Adelaide Bank has 87.8 per cent, and ING Direct has 87.6 per cent.Citibank, whose rating is subject to big month-to-month fluctuations, is at the bottom of the pack with a rating of 62.4 per cent.