-69.76% is the change from 830 to 251
Calculation steps:
[( 251 - 830 ) ÷ 830] x 100 = -69.76%
Formula
Percentage change = [(251 - 830) / 830] x 100
Subtract the new number by the original number
251 - 830 = -579
-579 ÷ 830 = -0.6975903614457831
-0.6975903614457831 x 100 = -69.76%