-63.33% is the change from 30 to 11
Calculation steps:
[( 11 - 30 ) ÷ 30] x 100 = -63.33%
Formula
Percentage change = [(11 - 30) / 30] x 100
Subtract the new number by the original number
11 - 30 = -19
-19 ÷ 30 = -0.6333333333333333
-0.6333333333333333 x 100 = -63.33%