-2.41% is the change from 870 to 849
Calculation steps:
[( 849 - 870 ) ÷ 870] x 100 = -2.41%
Formula
Percentage change = [(849 - 870) / 870] x 100
Subtract the new number by the original number
849 - 870 = -21
-21 ÷ 870 = -0.02413793103448276
-0.02413793103448276 x 100 = -2.41%