30.03% is the change from 666 to 866
Calculation steps:
[( 866 - 666 ) ÷ 666] x 100 = 30.03%
Formula
Percentage change = [(866 - 666) / 666] x 100
Subtract the new number by the original number
866 - 666 = 200
200 ÷ 666 = 0.3003003003003003
0.3003003003003003 x 100 = 30.03%