Kelly Clarkson and Carrie Underwood

With the new season of 'American Idol' just underway, several past contestants have proven their staying power at radio -- in multiple formats. Two such artists, Kelly Clarkson and Carrie Underwood, continue to lead the pack.

Kelly, who made her mark in pop music but earned a huge country following from her hit duet with Reba McEntire, 'Because of You,' had the most radio plays of any 'Al' finalist, with over 3.5 million spins since her win in 2002, according to Mediabase (via NY Daily News). Chris Daughtry, a finalist in 2006, came in second, with just over 2 million air plays, thanks to his huge crossover song, 'Home,' a hit at pop, country and Christian radio. Carrie came in right behind Chris, at just over 1.5 million plays. Like Chris, Carrie's first hit, 'Jesus, Take the Wheel,' was a No. 1 hit on pop, country and Christian radio. It also earned the singer two Grammy awards.

Mediabase also tallied the most popular songs at radio since 2002, and once again Kelly dominates the list, taking four of the top five slots. She had the most-played song with 'Breakaway,' with Carrie coming in a close second with 'Before He Cheats.' Kelly takes the rest of the slots in the top five with 'Since U Been Gone,' 'Because of You,' and 'Behind These Hazel Eyes.' Kelly also landed at both the ninth and tenth slots, with, respectively, 'Walk Away' and 'Miss Independent.'

Kelly may be leading the way at radio, but Carrie, who came on to the music scene three years after Kelly's Idol win, is certainly hot on her trail. Nominated for two Grammys on Jan. 31, she's following up her No. 1 hit, 'Cowboy Casanova,' with her latest single, 'Temporary Home,' currently in the Top 20.

Both Kelly and Carrie were recently named by 'Idol' judge Randy Jackson as his favorite winners.