There has been a sharp drop in the use of telephone banking services - consumers' least favoured way of banking - over the past couple of years, according to new research.Roy Morgan Research surveyed 50,000 people and found that 15 per cent use telephone banking regularly - down from 18.9 per cent two years ago.Satisfaction with phone banking, at 79.9 per cent, was the lowest rating of any form of retail banking.The most popular way of banking is online. The proportion of customers banking online has grown from 58.6 per cent to 62.2 per cent over the past two years.Internet banking via mobile devices has grown from 26.2 per cent to 33.6 per cent over the same period.The proportion of people using branches regularly has fallen from 35.5 per cent to 32.3 per cent over the two years.Customers who bank online give the service an average rating of 90.2 per cent, while customers who use branches give the service an average rating of 88.4 per cent.