Update:
1. Mahalia Jackson
2. Aretha Franklin
3. Katie Melua
4. Whitney Houston
5. Joan Baez
6. Norah Jones
7. Loreena McKennitt
8. Diana Krall
9. Joni Mitchel
11. Patti Smith
10. Lucinda Williams
11. Emmylou Haris
12. Eva Cassidy
13. Tracy Chapman
14. Mary Black
15. Joan Armatrading
16. Sinead O´Connor
17. Tina Turner
18. Sarah McLachlan
19. Kate Bush
20. Anny Lennox
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Keep on Rocking!