-79.03% is the change from 639 to 134
Calculation steps:
[( 134 - 639 ) ÷ 639] x 100 = -79.03%
Formula
Percentage change = [(134 - 639) / 639] x 100
Subtract the new number by the original number
134 - 639 = -505
-505 ÷ 639 = -0.7902973395931142
-0.7902973395931142 x 100 = -79.03%