-33.2% is the change from 512 to 342
Calculation steps:
[( 342 - 512 ) ÷ 512] x 100 = -33.2%
Formula
Percentage change = [(342 - 512) / 512] x 100
Subtract the new number by the original number
342 - 512 = -170
-170 ÷ 512 = -0.33203125
-0.33203125 x 100 = -33.2%