-83.33% is the change from 306 to 51
Calculation steps:
[( 51 - 306 ) ÷ 306] x 100 = -83.33%
Formula
Percentage change = [(51 - 306) / 306] x 100
Subtract the new number by the original number
51 - 306 = -255
-255 ÷ 306 = -0.8333333333333334
-0.8333333333333334 x 100 = -83.33%