-20.53% is the change from 838 to 666
Calculation steps:
[( 666 - 838 ) ÷ 838] x 100 = -20.53%
Formula
Percentage change = [(666 - 838) / 838] x 100
Subtract the new number by the original number
666 - 838 = -172
-172 ÷ 838 = -0.2052505966587112
-0.2052505966587112 x 100 = -20.53%