-3.43% is the change from 670 to 647
Calculation steps:
[( 647 - 670 ) ÷ 670] x 100 = -3.43%
Formula
Percentage change = [(647 - 670) / 670] x 100
Subtract the new number by the original number
647 - 670 = -23
-23 ÷ 670 = -0.034328358208955224
-0.034328358208955224 x 100 = -3.43%