-79.72% is the change from 646 to 131
Calculation steps:
[( 131 - 646 ) ÷ 646] x 100 = -79.72%
Formula
Percentage change = [(131 - 646) / 646] x 100
Subtract the new number by the original number
131 - 646 = -515
-515 ÷ 646 = -0.7972136222910217
-0.7972136222910217 x 100 = -79.72%