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)