-26.99% is the change from 915 to 668
Calculation steps:
[( 668 - 915 ) ÷ 915] x 100 = -26.99%
Formula
Percentage change = [(668 - 915) / 915] x 100
Subtract the new number by the original number
668 - 915 = -247
-247 ÷ 915 = -0.26994535519125684
-0.26994535519125684 x 100 = -26.99%