-2.9% is the change from 690 to 670
Calculation steps:
[( 670 - 690 ) ÷ 690] x 100 = -2.9%
Formula
Percentage change = [(670 - 690) / 690] x 100
Subtract the new number by the original number
670 - 690 = -20
-20 ÷ 690 = -0.028985507246376812
-0.028985507246376812 x 100 = -2.9%