-4.99% is the change from 421 to 400
Calculation steps:
[( 400 - 421 ) ÷ 421] x 100 = -4.99%
Formula
Percentage change = [(400 - 421) / 421] x 100
Subtract the new number by the original number
400 - 421 = -21
-21 ÷ 421 = -0.0498812351543943
-0.0498812351543943 x 100 = -4.99%