-93.86% is the change from 831 to 51
Calculation steps:
[( 51 - 831 ) ÷ 831] x 100 = -93.86%
Formula
Percentage change = [(51 - 831) / 831] x 100
Subtract the new number by the original number
51 - 831 = -780
-780 ÷ 831 = -0.9386281588447654
-0.9386281588447654 x 100 = -93.86%