-64.64% is the change from 280 to 99
Calculation steps:
[( 99 - 280 ) ÷ 280] x 100 = -64.64%
Formula
Percentage change = [(99 - 280) / 280] x 100
Subtract the new number by the original number
99 - 280 = -181
-181 ÷ 280 = -0.6464285714285715
-0.6464285714285715 x 100 = -64.64%