-74.6% is the change from 870 to 221
Calculation steps:
[( 221 - 870 ) ÷ 870] x 100 = -74.6%
Formula
Percentage change = [(221 - 870) / 870] x 100
Subtract the new number by the original number
221 - 870 = -649
-649 ÷ 870 = -0.7459770114942529
-0.7459770114942529 x 100 = -74.6%