-15.89% is the change from 321 to 270
Calculation steps:
[( 270 - 321 ) ÷ 321] x 100 = -15.89%
Formula
Percentage change = [(270 - 321) / 321] x 100
Subtract the new number by the original number
270 - 321 = -51
-51 ÷ 321 = -0.1588785046728972
-0.1588785046728972 x 100 = -15.89%