-3.52% is the change from 512 to 494
Calculation steps:
[( 494 - 512 ) ÷ 512] x 100 = -3.52%
Formula
Percentage change = [(494 - 512) / 512] x 100
Subtract the new number by the original number
494 - 512 = -18
-18 ÷ 512 = -0.03515625
-0.03515625 x 100 = -3.52%