-70.47% is the change from 850 to 251
Calculation steps:
[( 251 - 850 ) ÷ 850] x 100 = -70.47%
Formula
Percentage change = [(251 - 850) / 850] x 100
Subtract the new number by the original number
251 - 850 = -599
-599 ÷ 850 = -0.7047058823529412
-0.7047058823529412 x 100 = -70.47%