-80% is the change from 990 to 198
Calculation steps:
[( 198 - 990 ) ÷ 990] x 100 = -80%
Formula
Percentage change = [(198 - 990) / 990] x 100
Subtract the new number by the original number
198 - 990 = -792
-792 ÷ 990 = -0.8
-0.8 x 100 = -80%
Example