-84.32% is the change from 421 to 66
Calculation steps:
[( 66 - 421 ) ÷ 421] x 100 = -84.32%
Formula
Percentage change = [(66 - 421) / 421] x 100
Subtract the new number by the original number
66 - 421 = -355
-355 ÷ 421 = -0.8432304038004751
-0.8432304038004751 x 100 = -84.32%