2.8% is the change from 643 to 661
Calculation steps:
[( 661 - 643 ) ÷ 643] x 100 = 2.8%
Formula
Percentage change = [(661 - 643) / 643] x 100
Subtract the new number by the original number
661 - 643 = 18
18 ÷ 643 = 0.027993779160186624
0.027993779160186624 x 100 = 2.8%