-60.98% is the change from 820 to 320
Calculation steps:
[( 320 - 820 ) ÷ 820] x 100 = -60.98%
Formula
Percentage change = [(320 - 820) / 820] x 100
Subtract the new number by the original number
320 - 820 = -500
-500 ÷ 820 = -0.6097560975609756
-0.6097560975609756 x 100 = -60.98%