-23.09% is the change from 836 to 643
Calculation steps:
[( 643 - 836 ) ÷ 836] x 100 = -23.09%
Formula
Percentage change = [(643 - 836) / 836] x 100
Subtract the new number by the original number
643 - 836 = -193
-193 ÷ 836 = -0.23086124401913877
-0.23086124401913877 x 100 = -23.09%