-45.01% is the change from 391 to 215
Calculation steps:
[( 215 - 391 ) ÷ 391] x 100 = -45.01%
Formula
Percentage change = [(215 - 391) / 391] x 100
Subtract the new number by the original number
215 - 391 = -176
-176 ÷ 391 = -0.45012787723785164
-0.45012787723785164 x 100 = -45.01%