997.8% is the change from 91 to 999
Calculation steps:
[( 999 - 91 ) ÷ 91] x 100 = 997.8%
Formula
Percentage change = [(999 - 91) / 91] x 100
Subtract the new number by the original number
999 - 91 = 908
908 ÷ 91 = 9.978021978021978
9.978021978021978 x 100 = 997.8%