-17.63% is the change from 312 to 257
Calculation steps:
[( 257 - 312 ) ÷ 312] x 100 = -17.63%
Formula
Percentage change = [(257 - 312) / 312] x 100
Subtract the new number by the original number
257 - 312 = -55
-55 ÷ 312 = -0.1762820512820513
-0.1762820512820513 x 100 = -17.63%