-19.74% is the change from 836 to 671
Calculation steps:
[( 671 - 836 ) ÷ 836] x 100 = -19.74%
Formula
Percentage change = [(671 - 836) / 836] x 100
Subtract the new number by the original number
671 - 836 = -165
-165 ÷ 836 = -0.19736842105263158
-0.19736842105263158 x 100 = -19.74%