-2.71% is the change from 663 to 645
Calculation steps:
[( 645 - 663 ) ÷ 663] x 100 = -2.71%
Formula
Percentage change = [(645 - 663) / 663] x 100
Subtract the new number by the original number
645 - 663 = -18
-18 ÷ 663 = -0.027149321266968326
-0.027149321266968326 x 100 = -2.71%