-81.3% is the change from 909 to 170
Calculation steps:
[( 170 - 909 ) ÷ 909] x 100 = -81.3%
Formula
Percentage change = [(170 - 909) / 909] x 100
Subtract the new number by the original number
170 - 909 = -739
-739 ÷ 909 = -0.812981298129813
-0.812981298129813 x 100 = -81.3%