All album sales are adjusted to 1999 according to this
Eminem
SSLP-10 (10*1=10)
MMLP-24 (24*1.02=24,48)
TES-22 (22*1.19=26,18)
Encore-11 (11*1.34=14,74)
Relapse-4.5 (4,5*2.57=11.565)
Recovery-9m (9*2.81=25.29)
MMLP2-4,5 (4,5*3.24=14.58)
CCTH-9.5 (9.5*1.48=14.06)
Total=140.895
Britney
BOMT-25
OIDIA-22 (22*1.02=22.44)
Britney-11.5 (11.5*1.09=12.535)
In the Zone-8 (8*1.27=10.16)
GH-MP-7.1 (7.1*1.34=9.514)
Blackout-2.7 (2.7*1.86=5.022)
Circus-4m (4*2.13=8.52)
The singles collection-900k(0.9*2.57=2.313)
FF-1.9 (1.9*2.9=5.51)
BJ-0.65 (0.65*3.24=2.106)
Total=103.12
Adele
19 (7*2.13=14.91)
21 (28*2.9=81.2)
96.11m albums
Taylor swift
TS-6 (6*1.65=9.9)
SOTS-1 (1*1.86=1.86)
Fearless-9.5 (9.5*2.13=20.235)
SN-6 (6*2.81=16.86)
Red-6.5 (6.5*3=19.5)
1989-6.7 (6.7*3.68=24.656)
Total=93.011
Pink
Can't Take Me Home: 4M (4*1.02=4.08)
M!ssundaztood: 13M (1.09*13=14.17)
Try This: 3M (3*1.27=3.81)
I'm Not Dead: 6.5M (1.65*6.5=10.725)
Pink Box: 0.2M (0.2*1.86=0.372
Funhouse: 7M (7*2.13=14.91)
Funhouse: Live in Australia: 1M (1*2.57=2.57)
Greatest Hits...So Far!!!!: 4M (4*2.81=11.24)
The Truth About Love: 6M (6*3=18)
Total : 79.877
Rihanna
Music of the Sun - 1,450,000 (1.45*1.48=2.16m)
A Girl Like Me - 3,200,000 (3.2*1.65=5.28)
Good Girl Gone Bad - 9,000,000
(1.86*9=16.74)
Rated R - 3,200,000
(2.57*3.2=8.224)
Loud - 6,100,000
(2.81*6.1=17.141)
Talk That Talk - 3,850,000
(3.85*2.9=11.165)
Unapologetic - 3,650,000
(3.65*3=10.95)
71.66
Lady Gaga
TFM-17 (17*2.13=36.21)
Remix 1 (1*2.81=2.81)
BTW-7 (7*2.9=20.3)
Artpop ( 2*3.24=6.48)
C2C (1*3.68=3.68)
69.48m albums
Beyonce
DIL-10 (10*1.27=12.7m)
Bday-6.2 (6.2*1.65=10.23)
IASF-8 (8*2.13=17.04)
4-3.1 (3.1*2.9=8.99)
Beyonce-3.8(3.8*3.24=12.312)
61.272m albums (101.046 with destinys child)
Avril Lavigne
Let Go-17 (17*1.19=20.23)
UMS-10 (10*1.34=13.4)
TBDT- (7*1.86=13.02)
GL-1.65 (1.65*2.9=4.785)
AL-0,7 (0.7*3.24=2.268)
Total-53.703
Christina Aguilera
CA-15 (15*1=15)
MR-2 (2*1.02=2.04)
MKOC-1.5 (1.5*1.02=1.53)
Stripped-11 (11*1.27=13.97)
B2B-5 (5*1.65=8.25)
KGBADOH-1.5 (1.5*2.13=3.195)
Bionic-0.9 (0.9*2.81=2.529)
Burlesque-1.4 (1.4*2.81=3.934)
Lotus-0.55 (0.55*3=1.65)
Total=52.098m albums
Destinys child
The Writing's on the Wall – 12 (12*1=12)
Survivor – 10 (10*1.09=10.9)
Destiny's Fulfilled – 6,25(1.34*6.25=8.375)
#1's – 3,750,000 (3.75*1.48=5.55)
Destiny's Child – 1,750,000 (1.75*1=1.75)**=1.75
8 Days of Christmas – 1,100,000 (1.1*1.09=1.199)
Total
39.774m albums
Katy Perry
OOTB-4 (8.52)
TD-6.5 (6.5*2.81=18.265)
Prism-3.6 (3.5*3.24=11.664)
38.449m albums
Bruno Mars
DW&H-6.5m (6.5*2.81=18.265)
UJ-6.5 (6.5*3=19.5)
Total=37.765m