-70.31% is the change from 64 to 19
Calculation steps:
[( 19 - 64 ) ÷ 64] x 100 = -70.31%
Formula
Percentage change = [(19 - 64) / 64] x 100
Subtract the new number by the original number
19 - 64 = -45
-45 ÷ 64 = -0.703125
-0.703125 x 100 = -70.31%
Example