-37.3% is the change from 512 to 321
Calculation steps:
[( 321 - 512 ) ÷ 512] x 100 = -37.3%
Formula
Percentage change = [(321 - 512) / 512] x 100
Subtract the new number by the original number
321 - 512 = -191
-191 ÷ 512 = -0.373046875
-0.373046875 x 100 = -37.3%