-51.4% is the change from 321 to 156
Calculation steps:
[( 156 - 321 ) ÷ 321] x 100 = -51.4%
Formula
Percentage change = [(156 - 321) / 321] x 100
Subtract the new number by the original number
156 - 321 = -165
-165 ÷ 321 = -0.514018691588785
-0.514018691588785 x 100 = -51.4%