-3.8% is the change from 421 to 405
Calculation steps:
[( 405 - 421 ) ÷ 421] x 100 = -3.8%
Formula
Percentage change = [(405 - 421) / 421] x 100
Subtract the new number by the original number
405 - 421 = -16
-16 ÷ 421 = -0.03800475059382423
-0.03800475059382423 x 100 = -3.8%