-21.5% is the change from 800 to 628
Calculation steps:
[( 628 - 800 ) ÷ 800] x 100 = -21.5%
Formula
Percentage change = [(628 - 800) / 800] x 100
Subtract the new number by the original number
628 - 800 = -172
-172 ÷ 800 = -0.215
-0.215 x 100 = -21.5%