-62.24% is the change from 850 to 321
Calculation steps:
[( 321 - 850 ) ÷ 850] x 100 = -62.24%
Formula
Percentage change = [(321 - 850) / 850] x 100
Subtract the new number by the original number
321 - 850 = -529
-529 ÷ 850 = -0.6223529411764706
-0.6223529411764706 x 100 = -62.24%