-9.88% is the change from 850 to 766
Calculation steps:
[( 766 - 850 ) ÷ 850] x 100 = -9.88%
Formula
Percentage change = [(766 - 850) / 850] x 100
Subtract the new number by the original number
766 - 850 = -84
-84 ÷ 850 = -0.0988235294117647
-0.0988235294117647 x 100 = -9.88%