-85.05% is the change from 669 to 100
Calculation steps:
[( 100 - 669 ) ÷ 669] x 100 = -85.05%
Formula
Percentage change = [(100 - 669) / 669] x 100
Subtract the new number by the original number
100 - 669 = -569
-569 ÷ 669 = -0.8505231689088192
-0.8505231689088192 x 100 = -85.05%