-33.71% is the change from 964 to 639
Calculation steps:
[( 639 - 964 ) ÷ 964] x 100 = -33.71%
Formula
Percentage change = [(639 - 964) / 964] x 100
Subtract the new number by the original number
639 - 964 = -325
-325 ÷ 964 = -0.33713692946058094
-0.33713692946058094 x 100 = -33.71%