-61.41% is the change from 666 to 257
Calculation steps:
[( 257 - 666 ) ÷ 666] x 100 = -61.41%
Formula
Percentage change = [(257 - 666) / 666] x 100
Subtract the new number by the original number
257 - 666 = -409
-409 ÷ 666 = -0.6141141141141141
-0.6141141141141141 x 100 = -61.41%