Here’s the amount of time each candidate got:

Romney — 7:03, during 9 times
McCain — 5:09, during 4 times
Giuliani — 5:08, during 9 times
Thompson — 4:38, during 4 times
Huckabee — 4:14, during 5 times
Paul — 3:27, during 4 times
Tancredo — 2:20, during 4 times
Hunter — 2:16, during 3 times
(Thanks to Brad Funkhauser)