-7.8% is the change from 667 to 615
Calculation steps:
[( 615 - 667 ) ÷ 667] x 100 = -7.8%
Formula
Percentage change = [(615 - 667) / 667] x 100
Subtract the new number by the original number
615 - 667 = -52
-52 ÷ 667 = -0.07796101949025487
-0.07796101949025487 x 100 = -7.8%