-74.13% is the change from 831 to 215
Calculation steps:
[( 215 - 831 ) ÷ 831] x 100 = -74.13%
Formula
Percentage change = [(215 - 831) / 831] x 100
Subtract the new number by the original number
215 - 831 = -616
-616 ÷ 831 = -0.7412755716004813
-0.7412755716004813 x 100 = -74.13%