Just been going through playlists for the last 12 months and the top ten slowies were:
Angels - Robbie Williams
You Raise Me Up - Westlife
Listen To Your Heart - DHT ft. Edmee
We've Got Tonight - Lulu And Ronan Keating
How Do I Live (Radio Edit) - LeAnn Rimes
Fields of Gold - Eva Cassidy
When You Say Nothing At All - Ronan Keating
Sacrifice - Elton John
My Heart Will Go On [1998] - Celine Dion
Because of You - Kelly Clarkson
So Robbies still at the top at the moment but I think he's got that sinking feeling and will be slipping down.

