-6.23% is the change from 642 to 602
Calculation steps:
[( 602 - 642 ) ÷ 642] x 100 = -6.23%
Formula
Percentage change = [(602 - 642) / 642] x 100
Subtract the new number by the original number
602 - 642 = -40
-40 ÷ 642 = -0.06230529595015576
-0.06230529595015576 x 100 = -6.23%