-90.51% is the change from 643 to 61
Calculation steps:
[( 61 - 643 ) ÷ 643] x 100 = -90.51%
Formula
Percentage change = [(61 - 643) / 643] x 100
Subtract the new number by the original number
61 - 643 = -582
-582 ÷ 643 = -0.9051321928460342
-0.9051321928460342 x 100 = -90.51%