-98.47% is the change from 850 to 13
Calculation steps:
[( 13 - 850 ) ÷ 850] x 100 = -98.47%
Formula
Percentage change = [(13 - 850) / 850] x 100
Subtract the new number by the original number
13 - 850 = -837
-837 ÷ 850 = -0.9847058823529412
-0.9847058823529412 x 100 = -98.47%