-3.28% is the change from 670 to 648
Calculation steps:
[( 648 - 670 ) ÷ 670] x 100 = -3.28%
Formula
Percentage change = [(648 - 670) / 670] x 100
Subtract the new number by the original number
648 - 670 = -22
-22 ÷ 670 = -0.03283582089552239
-0.03283582089552239 x 100 = -3.28%