-68.75% is the change from 64 to 20
Calculation steps:
[( 20 - 64 ) ÷ 64] x 100 = -68.75%
Formula
Percentage change = [(20 - 64) / 64] x 100
Subtract the new number by the original number
20 - 64 = -44
-44 ÷ 64 = -0.6875
-0.6875 x 100 = -68.75%
Example