-62.07% is the change from 820 to 311
Calculation steps:
[( 311 - 820 ) ÷ 820] x 100 = -62.07%
Formula
Percentage change = [(311 - 820) / 820] x 100
Subtract the new number by the original number
311 - 820 = -509
-509 ÷ 820 = -0.6207317073170732
-0.6207317073170732 x 100 = -62.07%