-99.39% is the change from 661 to 4
Calculation steps:
[( 4 - 661 ) ÷ 661] x 100 = -99.39%
Formula
Percentage change = [(4 - 661) / 661] x 100
Subtract the new number by the original number
4 - 661 = -657
-657 ÷ 661 = -0.9939485627836612
-0.9939485627836612 x 100 = -99.39%