3950% is the change from 2 to 81
Calculation steps:
[( 81 - 2 ) ÷ 2] x 100 = 3950%
Formula
Percentage change = [(81 - 2) / 2] x 100
Subtract the new number by the original number
81 - 2 = 79
79 ÷ 2 = 39.5
39.5 x 100 = 3950%
Example