While USB 2.0 on paper gets up to 60 megabytes/second, in reality it never reaches that. Best I have come across was about 40 or so.
That said, As the user above says, it depends on the card you have.
Also newer USB 3.0 sticks(but watch it as many are just not that fast at all) can get 50-100 megabytes per second for writes with ease(and it will only get better as time goes on). Small files tends to slow the sticks down as well.
I have seen a cheap A-DATA USB 3.0 stick that is rated at 50 write and 100 read, it gets about 40/80 and that is not too bad at all.