-27.55% is the change from 911 to 660
Calculation steps:
[( 660 - 911 ) ÷ 911] x 100 = -27.55%
Formula
Percentage change = [(660 - 911) / 911] x 100
Subtract the new number by the original number
660 - 911 = -251
-251 ÷ 911 = -0.27552140504939626
-0.27552140504939626 x 100 = -27.55%