81900% is the change from 1 to 820
Calculation steps:
[( 820 - 1 ) ÷ 1] x 100 = 81900%
Formula
Percentage change = [(820 - 1) / 1] x 100
Subtract the new number by the original number
820 - 1 = 819
819 ÷ 1 = 819
819 x 100 = 81900%
Example