My GF was a proof operator at a bank for a few years... bascially she would get a stack of checks and she would have to add up all the total amounts in the stack and make sure it adds up to what the computer said it did.

So 10-key was all she did for years! Holy crap I thought I was average at 10-key, maybe a little above on a good day. She can type out like 30-digit numbers and I'm still reaching for the NUM LOCK!