-80.52% is the change from 421 to 82
Calculation steps:
[( 82 - 421 ) ÷ 421] x 100 = -80.52%
Formula
Percentage change = [(82 - 421) / 421] x 100
Subtract the new number by the original number
82 - 421 = -339
-339 ÷ 421 = -0.8052256532066508
-0.8052256532066508 x 100 = -80.52%