-78.79% is the change from 646 to 137
Calculation steps:
[( 137 - 646 ) ÷ 646] x 100 = -78.79%
Formula
Percentage change = [(137 - 646) / 646] x 100
Subtract the new number by the original number
137 - 646 = -509
-509 ÷ 646 = -0.7879256965944272
-0.7879256965944272 x 100 = -78.79%