-61.37% is the change from 831 to 321
Calculation steps:
[( 321 - 831 ) ÷ 831] x 100 = -61.37%
Formula
Percentage change = [(321 - 831) / 831] x 100
Subtract the new number by the original number
321 - 831 = -510
-510 ÷ 831 = -0.6137184115523465
-0.6137184115523465 x 100 = -61.37%