-3.11% is the change from 643 to 623
Calculation steps:
[( 623 - 643 ) ÷ 643] x 100 = -3.11%
Formula
Percentage change = [(623 - 643) / 643] x 100
Subtract the new number by the original number
623 - 643 = -20
-20 ÷ 643 = -0.03110419906687403
-0.03110419906687403 x 100 = -3.11%