-50.41% is the change from 615 to 305
Calculation steps:
[( 305 - 615 ) ÷ 615] x 100 = -50.41%
Formula
Percentage change = [(305 - 615) / 615] x 100
Subtract the new number by the original number
305 - 615 = -310
-310 ÷ 615 = -0.5040650406504065
-0.5040650406504065 x 100 = -50.41%