-38.89% is the change from 18 to 11
Calculation steps:
[( 11 - 18 ) ÷ 18] x 100 = -38.89%
Formula
Percentage change = [(11 - 18) / 18] x 100
Subtract the new number by the original number
11 - 18 = -7
-7 ÷ 18 = -0.3888888888888889
-0.3888888888888889 x 100 = -38.89%