-2.56% is the change from 664 to 647
Calculation steps:
[( 647 - 664 ) ÷ 664] x 100 = -2.56%
Formula
Percentage change = [(647 - 664) / 664] x 100
Subtract the new number by the original number
647 - 664 = -17
-17 ÷ 664 = -0.025602409638554216
-0.025602409638554216 x 100 = -2.56%