How many digits?

I called a financial services company about an account I have with them. First thing I get is the automated answering thing, which I don't really mind too much. But what I loved was then the voice said "now enter your account number, one digit at a time". I can only assume that they say this in the belief that if they don't, I'll just mash down all the numbers on the phone keypad at the same time. D'oh!