Bey, Brit, Shakira, Jlo and Xtina are 90s. Katy, Gaga, and Miley are 00's.
Their way into super stardom was in the 00s so I put them to 00s. Shakira wasn't worldwide famous before Laundry Service.
Britney's debut was in 1998 but I think she's more of a 00s artist than a 90s artist.