-78.48% is the change from 646 to 139
Calculation steps:
[( 139 - 646 ) ÷ 646] x 100 = -78.48%
Formula
Percentage change = [(139 - 646) / 646] x 100
Subtract the new number by the original number
139 - 646 = -507
-507 ÷ 646 = -0.7848297213622291
-0.7848297213622291 x 100 = -78.48%