-15.15% is the change from 66 to 56
Calculation steps:
[( 56 - 66 ) ÷ 66] x 100 = -15.15%
Formula
Percentage change = [(56 - 66) / 66] x 100
Subtract the new number by the original number
56 - 66 = -10
-10 ÷ 66 = -0.15151515151515152
-0.15151515151515152 x 100 = -15.15%