Just a bit of info, album sales only:
US (Soundscan): Mariah 54M, Jans 26M
Japan: Mariah 15M (biggest selling foreign artist), Jans 1.8M
Germany: Mariah 2.1M, Jans 1M
UK: Mariah 5.5M, Jans 2.5 M
France: Mariah 4.5M, Jans 900k
Australia: Mariah 2.4M, Jans 600k
Canada: Mariah 4.1M, Jans 1.1M
South Korea: 3.14M for Music Box, Daydream and Merry Christmas combined sales. Not even including her other albums. One of the 4 biggest selling artists along with The Beatles, Queen and Michael Jackson. no info on Jans .....
Brazil: 1.68M (8th biggest selling foreign artist), also hold the record for longest stay at #1 on the single charts. Jans 150k
Italy: Mariah 350k, Jans 100k
These are the 10 biggest markets in the world.