-3.04% is the change from 691 to 670
Calculation steps:
[( 670 - 691 ) ÷ 691] x 100 = -3.04%
Formula
Percentage change = [(670 - 691) / 691] x 100
Subtract the new number by the original number
670 - 691 = -21
-21 ÷ 691 = -0.030390738060781478
-0.030390738060781478 x 100 = -3.04%