-70.26% is the change from 306 to 91
Calculation steps:
[( 91 - 306 ) ÷ 306] x 100 = -70.26%
Formula
Percentage change = [(91 - 306) / 306] x 100
Subtract the new number by the original number
91 - 306 = -215
-215 ÷ 306 = -0.7026143790849673
-0.7026143790849673 x 100 = -70.26%