Keep buying ‘Rude Boy’ because it’s doing great on the charts! Here’s the positions of iTunes:

UK : 2
Denmark : 2
Ireland : 3
France : 3
U.S : 4
Australia : 4
Switzerland : 6
Luxembourg : 9

And the official charts:

UK : 6
Ireland : 6
Australia : 8
Finland : 12
Europe : 19
U.S : 23
Denmark : 25
New Zealand : 25
Switzerland : 30
Canada : 42
Czech Republic : 78

(Also, on the iTunes Pop Chart, Rude Boy is #1 in Denmark!)