-50% is the change from 624 to 312
Calculation steps:
[( 312 - 624 ) ÷ 624] x 100 = -50%
Formula
Percentage change = [(312 - 624) / 624] x 100
Subtract the new number by the original number
312 - 624 = -312
-312 ÷ 624 = -0.5
-0.5 x 100 = -50%
Example