-39.76% is the change from 850 to 512
Calculation steps:
[( 512 - 850 ) ÷ 850] x 100 = -39.76%
Formula
Percentage change = [(512 - 850) / 850] x 100
Subtract the new number by the original number
512 - 850 = -338
-338 ÷ 850 = -0.3976470588235294
-0.3976470588235294 x 100 = -39.76%