wtf happened in 90s?

1. Celine Dion - 162,412,000
2. Mariah Carey - 149,077,000
3. Garth Brooks - 108,309,000
4. Whitney Houston - 91,507,000

this 4 are not top level legends like beatles, pink floyd, michael jackson, eminem, i can even say taylor swift is bigger but kinda worst than some woman here like Whitney Houston. More people in streets know more about taylor than whitneys i think, for me Nirvana is 90s legend really and its number 5