-36.21% is the change from 660 to 421
Calculation steps:
[( 421 - 660 ) ÷ 660] x 100 = -36.21%
Formula
Percentage change = [(421 - 660) / 660] x 100
Subtract the new number by the original number
421 - 660 = -239
-239 ÷ 660 = -0.3621212121212121
-0.3621212121212121 x 100 = -36.21%