-61.1% is the change from 820 to 319
Calculation steps:
[( 319 - 820 ) ÷ 820] x 100 = -61.1%
Formula
Percentage change = [(319 - 820) / 820] x 100
Subtract the new number by the original number
319 - 820 = -501
-501 ÷ 820 = -0.6109756097560975
-0.6109756097560975 x 100 = -61.1%