-17.7% is the change from 305 to 251
Calculation steps:
[( 251 - 305 ) ÷ 305] x 100 = -17.7%
Formula
Percentage change = [(251 - 305) / 305] x 100
Subtract the new number by the original number
251 - 305 = -54
-54 ÷ 305 = -0.17704918032786884
-0.17704918032786884 x 100 = -17.7%