-59.78% is the change from 639 to 257
Calculation steps:
[( 257 - 639 ) ÷ 639] x 100 = -59.78%
Formula
Percentage change = [(257 - 639) / 639] x 100
Subtract the new number by the original number
257 - 639 = -382
-382 ÷ 639 = -0.5978090766823161
-0.5978090766823161 x 100 = -59.78%