-75% is the change from 800 to 200
Calculation steps:
[( 200 - 800 ) ÷ 800] x 100 = -75%
Formula
Percentage change = [(200 - 800) / 800] x 100
Subtract the new number by the original number
200 - 800 = -600
-600 ÷ 800 = -0.75
-0.75 x 100 = -75%
Example