-50% is the change from 636 to 318
Calculation steps:
[( 318 - 636 ) ÷ 636] x 100 = -50%
Formula
Percentage change = [(318 - 636) / 636] x 100
Subtract the new number by the original number
318 - 636 = -318
-318 ÷ 636 = -0.5
-0.5 x 100 = -50%
Example