-66.57% is the change from 661 to 221
Calculation steps:
[( 221 - 661 ) ÷ 661] x 100 = -66.57%
Formula
Percentage change = [(221 - 661) / 661] x 100
Subtract the new number by the original number
221 - 661 = -440
-440 ÷ 661 = -0.6656580937972768
-0.6656580937972768 x 100 = -66.57%