Popular Female Singers in the past 2 decades


Hi, can you name 10 most popular/favorite female singers (vocalist, artist) in the past 2 decades?

I want to collect the CDs for these singers and very often I heard those songs (mostly pop, movie theme sound track, etc) on radio FM103.5 or 107.9. But I don't remember or recognize their names or the songs.

Celine Dion and Britney Spears are just 2 examples. Thanks.
r0817
Most Popular female singers in the past 20 years?

Mariah Carey
Christina Aguilera
Janet Jackson
Natalie Cole
Diana Krall
Sade
Madonna
Whitney Houston
Beyonce
Lady Gaga
all of the above plus,
Alison Krauss
Lisa Hannigan
Sarah McLaughlin
Paula Cole
Alanis Morissette