-87.77% is the change from 646 to 79
Calculation steps:
[( 79 - 646 ) ÷ 646] x 100 = -87.77%
Formula
Percentage change = [(79 - 646) / 646] x 100
Subtract the new number by the original number
79 - 646 = -567
-567 ÷ 646 = -0.8777089783281734
-0.8777089783281734 x 100 = -87.77%