-70.12% is the change from 840 to 251
Calculation steps:
[( 251 - 840 ) ÷ 840] x 100 = -70.12%
Formula
Percentage change = [(251 - 840) / 840] x 100
Subtract the new number by the original number
251 - 840 = -589
-589 ÷ 840 = -0.7011904761904761
-0.7011904761904761 x 100 = -70.12%