-18.53% is the change from 421 to 343
Calculation steps:
[( 343 - 421 ) ÷ 421] x 100 = -18.53%
Formula
Percentage change = [(343 - 421) / 421] x 100
Subtract the new number by the original number
343 - 421 = -78
-78 ÷ 421 = -0.18527315914489312
-0.18527315914489312 x 100 = -18.53%