-6.65% is the change from 421 to 393
Calculation steps:
[( 393 - 421 ) ÷ 421] x 100 = -6.65%
Formula
Percentage change = [(393 - 421) / 421] x 100
Subtract the new number by the original number
393 - 421 = -28
-28 ÷ 421 = -0.0665083135391924
-0.0665083135391924 x 100 = -6.65%