MacBook Pro HD Size?

Hello every one... I'm new to this forum and perhaps this question has been asked before. I just bought a brand new MacBook Pro this past Thursday which till now I'm more than willing to share the next couple of years with it!! When I bought it said that it had a 200gb Hard Drive in the advertisement but in my MBP properties it only shows 185.99gb. Is this normal or is this a mistake?? The rest is fine 2gb memory and 2.4 Intel Core Duo I'm just have a dought on the HD size.

Any one?

CHEERS!!