Roll a 1d100.

(Can not be rolled) Hopeless -5
Feeble -4
Pityful -3
Poor -2
Mediocre -1
Average +0
Good +1
Excellent +2
Superior +3
Remarkable +4
(Can not to rolled from here on)
Incredible +5
Splendid +6
Acceptional +7
Fantastic +8
Uncanny +9
Exceptional +10
Outstanding +11
Impeccable +12
Marvelous +13
Amazing +14
Magnificent +15
Wonderous +16
Stupefying +17
Sensational +18
Monumentous +19
Mindblowing +20
Unearthly 21+