-20.43% is the change from 837 to 666
Calculation steps:
[( 666 - 837 ) ÷ 837] x 100 = -20.43%
Formula
Percentage change = [(666 - 837) / 837] x 100
Subtract the new number by the original number
666 - 837 = -171
-171 ÷ 837 = -0.20430107526881722
-0.20430107526881722 x 100 = -20.43%