-79.84% is the change from 491 to 99
Calculation steps:
[( 99 - 491 ) ÷ 491] x 100 = -79.84%
Formula
Percentage change = [(99 - 491) / 491] x 100
Subtract the new number by the original number
99 - 491 = -392
-392 ÷ 491 = -0.7983706720977597
-0.7983706720977597 x 100 = -79.84%