-79.9% is the change from 209 to 42
Calculation steps:
[( 42 - 209 ) ÷ 209] x 100 = -79.9%
Formula
Percentage change = [(42 - 209) / 209] x 100
Subtract the new number by the original number
42 - 209 = -167
-167 ÷ 209 = -0.7990430622009569
-0.7990430622009569 x 100 = -79.9%