The percentage of Australian banks' personal customers who were "very" or "fairly" satisfied with their financial institution in the six months to August 2016 was 81.6 per cent. This increase from July 2016 (81.5 per cent) is so small it's almost a rounding error on Roy Morgan's Single Source survey of 50,000 people annually.This current level, though, is well above the long-term average and is just below the 20-year high (82.9 per cent) recorded in 2015. Roy Morgan said the improvements seen over the last month were due to increased satisfaction levels among non-home loan customers (up 0.2 of a percentage point to 81.7 per cent), in contrast to the readings on home-loan customer satisfaction, which declined 0.6 percentage point to 79.1 per cent. The mortgage customers of each of the Big Four banks, in particular, continued to drag on their overall satisfaction measures, despite historically low home-loan rates. On Roy Morgan's numbers, overall customer satisfaction with the Big Four banks remained unchanged from July to August at 79.7 per cent but their home-loan customers' satisfaction declined by almost a whole percentage point to 75.9 per cent overall. Their non-home loan customer satisfaction, in contrast, increased by 0.2 point to 80.6 per cent over the month.NAB was the only one of the major banks to show an increase in home-loan customer satisfaction (up 0.2 per cent points to 73.2 per cent), although its non-home loan customers remained markedly more satisfied (79.2 per cent).Mortgage customers of the CBA are the furthest behind the satisfaction of their non-home loan customers (75.9 per cent compared to 82.5 per cent)."A potential reason for lower home-loan customer satisfaction is the very high levels of adverse publicity that the Big Four attract when they don't pass on the full interest rate reductions announced by the RBA," said Norman Morris, industry communications director, Roy Morgan Research."On the positive side, it appears that bank customers are moving over to online banking and are giving these newer channels generally much higher satisfaction scores than for branches. This trend is a likely contributor to improved overall customer satisfaction."Bendigo Bank has the highest home-loan customer satisfaction (of the top ten) with 96.2 per cent, followed by ING Direct (93.4 per cent). These two are well clear of the field with the next best being BankWest (85.1 per cent). ANZ (78.5 per cent) has the highest percentage of "satisfied" home-loan customers among the Big Four.