I'll repost the list here for reference:

1) J.K Rowling (c. 450 million)

2) Stephen King (c. 350 million)

3) JRR Tolkien (c. 300 million)

4) CS Lewis (120 million+)

5) Stephanie Meyer (116 million)

6) Anne Rice (100 million)

7) Robert Jordan (80 million+)

8) Sir Terry Pratchett (65 million+)

9) Richard Adams (50 million+)

10) Suzanne Collins (50 million+)

11) Christopher Paolini (33 million)

12) R.A. Salvatore (30 million+)

13) Kaoru Kurimoto (28 million)

14) George Orwell (25 million+)

15) Terry Goodkind (25 million)

16) Cassandra Clare (24 million)

17) Terry Brooks (21 million+)

18) Eoin Colfer (21 million)

19) George R.R. Martin (20 million+)

20) Isaac Asimov (20 million+)

21) Margaret Weis & Tracy Hickman (c. 20 million)

22) Brian Jacquies (c. 20 million)

23) Kazumasa Hirai (c. 20 million)

24) Charlaine Harris (c. 20 million)

25) Frank Herbert (18 million)

26) Hideyuki Kikuchi (18 million)

27) Diana Gabaldon (17 million)

28) Douglas Adams (16 million)

29) Kevin J. Anderson (16 million)

30) Raymond E. Feist (15 million+)

31) Rick Riordan (15 million)

32) Philip Pullman (15 million)

33) Yoshiki Tanaka (15 million)

34) Stephen Donaldson (10 million)

35) Neil Gaiman (10 million + )

36) Alice Sebold (10 million+)

37) Madeline L'Engle (10 million+)

38) Timothy Zahn (8 million)

39) Laurell K. Hamilton (6 million+)

40) Frank L. Baum (5 million+)

41) Guy Gavriel Kay (3 million)

42) John Ringo (3 million)

43) Joe Abercrombie (3 million)

44) Harry Turtledove (2.5 million)

45) Peter F. Hamilton (2 million+)

46) Dan Abnett (1.2 million+)

47) Robin Hobb (1 million+)

48) David Gemmell (1 million+)

49) Steven Erikson (1 million+)

50) Trudi Canavant (1 million+)

51) Chris Wooding (450,000+)

52) R. Scott Bakker (125,000+)

I think I only got up to 25 that I finished reading, but I'm sure that score will be easily beaten here.