-77.1% is the change from 310 to 71
Calculation steps:
[( 71 - 310 ) ÷ 310] x 100 = -77.1%
Formula
Percentage change = [(71 - 310) / 310] x 100
Subtract the new number by the original number
71 - 310 = -239
-239 ÷ 310 = -0.7709677419354839
-0.7709677419354839 x 100 = -77.1%