-78.63% is the change from 800 to 171
Calculation steps:
[( 171 - 800 ) ÷ 800] x 100 = -78.63%
Formula
Percentage change = [(171 - 800) / 800] x 100
Subtract the new number by the original number
171 - 800 = -629
-629 ÷ 800 = -0.78625
-0.78625 x 100 = -78.63%