-15.89% is the change from 642 to 540
Calculation steps:
[( 540 - 642 ) ÷ 642] x 100 = -15.89%
Formula
Percentage change = [(540 - 642) / 642] x 100
Subtract the new number by the original number
540 - 642 = -102
-102 ÷ 642 = -0.1588785046728972
-0.1588785046728972 x 100 = -15.89%