-3.2% is the change from 657 to 636
Calculation steps:
[( 636 - 657 ) ÷ 657] x 100 = -3.2%
Formula
Percentage change = [(636 - 657) / 657] x 100
Subtract the new number by the original number
636 - 657 = -21
-21 ÷ 657 = -0.0319634703196347
-0.0319634703196347 x 100 = -3.2%