-83.1% is the change from 420 to 71
Calculation steps:
[( 71 - 420 ) ÷ 420] x 100 = -83.1%
Formula
Percentage change = [(71 - 420) / 420] x 100
Subtract the new number by the original number
71 - 420 = -349
-349 ÷ 420 = -0.830952380952381
-0.830952380952381 x 100 = -83.1%