Full details at the link, but the quick version is as follows:

If an author is not present, that's likely because official sales figures have not been released yet. Brandon Sanderson and Patrick Rothfuss, for example, should definitely be on here but as they have no official figures, I can't place them. That's also true for older authors like Philip K. Dick.

Authors listed in [] are writers who have mostly published non-SFF, and where it is impossible to extract their non-SFF sales from their SFF ones. Their total sales are listed for comparison purposes.

1) J.K. Rowling (c. 450 million)
2) Stephen King (c. 350 million)
3) JRR Tolkien (c. 300 million)
[Dean Koontz (c. 200 million)]
[Michael Crichton (200 million)]
4) Anne Rice (136 million)
5) CS Lewis (120 million+)
6) Stephanie Meyer (116 million)
7) Edgar Rice Burroughs (100 million+)
Sir Arthur C. Clarke (100 million+)
9) Andre Norton (90 million+)
10) Sir Terry Pratchett 5 million+)
11) Robert Jordan 0 million+)
[John Saul (60 million+)]
12) James Herbert (54 million+)
13) Richard Adams (50 million+)
14) Suzanne Collins (50 million+)
[Dennis Wheatley (50 million)]
[Jean M. Auel (45 million)]
[Morgan Llywelyn (40 million)]
15) Christopher Paolini (39 million)
16) Michael Ende (35 million)
17) Charlaine Harris (32.5 million)
1 Stanislaw Lem (30 million+)
19) R.A. Salvatore (30 million+)
20) Sherrilyn Kenyon (30 million+)
21) Robert Heinelin (30 million+)
22) George R.R. Martin (28 million+)
23) Kaoru Kurimoto (28 million)
24) Terry Brooks (26.5 million)
25) George Orwell (25 million+)
26) Marion Zimmer Bradley (25 million+)
27) Darren Shan (25 million+)
2 Terry Goodkind (25 million+)
29) Diana Gabaldon (25 million)
30) Cassandra Clare (24 million)
31) Kevin J. Anderson (23 million)
32) Eoin Colfer (21 million)
33) Isaac Asimov (20 million+)
34) Margaret Weis (c. 20 million)
35) Tracy Hickman (c. 20 million)
36) Brian Jacques (c. 20 million)
37) Kazumasa Hirai (c. 20 million)
3 Raymond E. Feist (20 million+)
39) Michael Moorcock (20 million)
40) Mercedes Lackey (20 million)
41) David Eddings (18 million+)
42) Frank Herbert (18 million)
43) Hideyuki Kikuchi (18 million)
44) Anne McCaffrey (18 million+)
45) Tad Williams (17 million)
46) Larry Niven (17 million)
47) Douglas Adams (16 million)
4 Brandon Sanderson (15 million+) (12 million WoT)
49) Rick Riordan (15 million)
50) Philip Pullman (15 million)
51) Yoshiki Tanaka (15 million)
52) Timothy Zahn (15 million)
53) Diana Wynne Jones (10 million+)
54) Robert E. Howard (10 million+)
55) Stephen Donaldson (10 million)
56) Neil Gaiman (10 million + )
57) Alice Sebold (10 million+)
5 Madeline L'Engle (10 million+)
59) Jerry Pournell (10 million+)
60) Chris Bunch (10 million+)
61) Allan Cole (10 million+)
62) Peter Straub (10 million+)
63) Frederik Pohl (10 million+)
64) Cyril M. Kornbluth (10 million+)
65) Gordon R. Dickson (10 million+)
66) Ray Bradbury million+)
67) Christopher Golden million+)
6 F. Paul Wilson million+)
[Bernard Cornwell (7 million+)]
69) David Weber (7 million)
70) Orson Scott Card (7 million+)
71) Roger Zelazny (6.5 million+)
72) William Gibson (6.5 million+)
73) Peter S. Beagle (6 million+)
74) Gregory Maguire (6 million+)
74) Laurell K. Hamilton (6 million+)
76) Jim Butcher (6 million+)
77) Jonathan Stroud (6 million+)
7 Barbara Hambly (6 million+)
79) L. Frank Baum (5 million+)
80) Daniel Keyes (5 million+)
81) Garth Nix (5 million)
82) Robert R. McCammon (5 million+)
83) Vonda N. McIntyre (5 million+)
84) Audrey Niffenegger (5 million+)
85) Sergei Lukyanenko (5 million+)
86) Frank Schatzing (4.2 million+)
87) Fritz Leiber (4 million+)
8 Lian Hearn (4 million)
89) David Drake (4 million)
90) Veronica Roth (4 million)
91) Tamora Pierce (4 million+)
92) Aaron Allston (3.3. million+)
93) Robert Harris (3 million+) (SF only)
94) Alan Dean Foster (3 million+)
95) Ursula K. Le Guin (3 million+)
96) Guy Gavriel Kay (3 million)
97) Lloyd Alexander (3 million)
9 Dan Abnett (3 million+)
99) John Ringo (3 million)
100) Joe Abercrombie (3 million)
101) Margaret Atwood (3 million+) (SF only)
102) Robert Silverberg (3 million+)
103) Eric Flint (3 million)
104) Scott Westerfield (3 million+)
105) Robert Asprin (3 million)
106) Rick Hautala (3 million+)
107) Brian Lumley (3 million+)
10 Neal Stephenson (3 million+)
109) Simon R. Green (2.7 million)
110) Kim Stanley Robinson (2.5 million+)
111) Harry Turtledove (2.5 million)
112) S.M. Stirling (2.5 million)
113) Michelle Paver (2.5 million+)
114) Max Brooks (2.4 million+)
115) James Dashner (2.3 million+)
116) Susan Cooper (2 million+)
117) Hans Dominik (2 million+)
11 Peter F. Hamilton (2 million+)
119) Brent Weeks (2 million)
120) Andrzej Sapkowski (2 million+)
121) Lois McMaster Bujold (2 million)
122) Katherine Kurtz (2 million)
123) Trudi Canavan (2 million+)
124) Stephen Lawhead (2 million+)
125) Robert Rankin (2 million+)
126) Maggie Stiefvater (2 million+)
127) Gregory Benford (2 million+)
12 Greg Bear (2 million+)
129) Jacqueline Carey (2 million+)
130) Piers Anthony (2 million+)
131) L.E. Modesitt, Jr. (2 million+)
132) David Gemmell (2 million+)
133) Justin Cronin (2 million+)
134) Kevin Crossley-Holland (2 million+)
135) Melanie Rawn (1.8 million+)
136) Jennifer Roberson (1.7 million)
137) Elizabeth Moon (1.5 million+)
13 Deborah Harkness (1.5 million+)
139) Susanna Clarke (1.5 million+)
140) Markus Heitz (1.5 million+)
141) Libba Bray (1.5 million+)
142) Seth Grahame-Smith (1.4 million+)
143) Dan Simmons (1.25 million+)
144) Stan Nicholls (1.25 million+)
145) Naomi Novik (1.2 million+)
146) Jack Campbell (1.2 million+)
147) Tanya Huff (1.2 million+)
14 Iain M. Banks (1.1 million+) (SF only)
149) Kelley Armstrong (1 million+)
150) Samuel R. Delany (1 million+)
151) Ed Greenwood (1 million+)
152) Paul S. Kemp (1 million+)
153) Connie Willis (1 million)
154) Sara Douglass (1 million)
155) Robin Hobb (1 million+)
156) Steven Erikson (1 million+)
157) Alastair Reynolds (1 million+)
15 Jasper Fforde (1 million+)
159) Ian Irvine (1 million+)
160) Richard A. Knaak (1 million+)
161) Katherine Kerr (1 million+)
162) Dave Duncan (1 million+)
163) A.C. Crispin (1 million+)
164) Hugh Howey (1 million+)
165) Joe Haldeman (1 million+)
166) Glen Cook (1 million+)
167) David Brin (1 million+)
16 Henry N. Beard (1 million+)
169) Douglas C. Kenney (1 million+)
170) Alexey Pehov (1 million+)
171) John Gregory Betancourt (1 million+)
172) Jo Clayton (1 million+)
173) Christie Golden (1 million+)
174) Drew Karpyshyn (1 million+)
175) David Mitchell (1 million+)
176) Ransom Riggs (1 million+)
177) Elizabeth Haydon (1 million+)
17 Peter V. Brett (925,000)
179) Chris Wooding (750,000+)
180) William King (750,000+)
181) Erin Morgenstern (650,000+)
182) Janny Wurts (500,000+)
183) Kevin Hearne (500,000+)
184) Alison Croggon (500,000+)
185) Michael Gerber (500,000+)
186) Hugh Cook (500,000+)
187) Gail Carriger (400,000+)
18 Gail Z. Martin (400,000+)
189) Lawrence Watt Evans aka Nathan Archer (400,000+)
190) Ben Aaronovitch (400,000+)
191) Lynn Flewelling (350,000)
192) Kate Elliott (300,000+)
193) Ernest Cline (300,000)
194) Mark Smith aka Jonathan Wylie aka Julia Gray (300,000+)
195) Julia Smith aka Jonathan Wylie aka Julia Gray (300,000+)
196) Scott Lynch (300,000+)
197) J.V. Jones (250,000+)
19 Mark Lawrence (250,000+)
199) Michael J. Sullivan (250,000+)
200) Karen Miller (250,000+)
201) Sharon Lee (250,000+)
202) Steve Miller (250,000+)
203) Karen Russell (210,000+)
204) James Barclay (200,000+)
205) R. Scott Bakker (200,000+)
206) Paolo Bacigalupi (200,000+)
207) Jaye Wells (200,000+)
20 David Dalglish (175,000+)
209) Daniel H. Wilson (160,000+)
210) Adam Roberts (150,000+)
211) Glen Duncan (150,000+)
212) Glenda Larke (120,000+)
213) James Lovegrove (100,000+)
214) Tom Lloyd (70,000+)
215) Russell Kirkpatrick (70,000+)
216) Hannu Rajaniemi (40,000+)

ETA: Yes, there's crazy smileys all over the above thanks to the board's oddball formatting. I can't be bothered to fix every single one, but I think you can work out what the numbers are supposed to be