-3.26% is the change from 644 to 623
Calculation steps:
[( 623 - 644 ) ÷ 644] x 100 = -3.26%
Formula
Percentage change = [(623 - 644) / 644] x 100
Subtract the new number by the original number
623 - 644 = -21
-21 ÷ 644 = -0.03260869565217391
-0.03260869565217391 x 100 = -3.26%