-67.21% is the change from 305 to 100
Calculation steps:
[( 100 - 305 ) ÷ 305] x 100 = -67.21%
Formula
Percentage change = [(100 - 305) / 305] x 100
Subtract the new number by the original number
100 - 305 = -205
-205 ÷ 305 = -0.6721311475409836
-0.6721311475409836 x 100 = -67.21%