-20.48% is the change from 83 to 66
Calculation steps:
[( 66 - 83 ) ÷ 83] x 100 = -20.48%
Formula
Percentage change = [(66 - 83) / 83] x 100
Subtract the new number by the original number
66 - 83 = -17
-17 ÷ 83 = -0.20481927710843373
-0.20481927710843373 x 100 = -20.48%