-33.02% is the change from 321 to 215
Calculation steps:
[( 215 - 321 ) ÷ 321] x 100 = -33.02%
Formula
Percentage change = [(215 - 321) / 321] x 100
Subtract the new number by the original number
215 - 321 = -106
-106 ÷ 321 = -0.3302180685358255
-0.3302180685358255 x 100 = -33.02%