-60.72% is the change from 639 to 251
Calculation steps:
[( 251 - 639 ) ÷ 639] x 100 = -60.72%
Formula
Percentage change = [(251 - 639) / 639] x 100
Subtract the new number by the original number
251 - 639 = -388
-388 ÷ 639 = -0.6071987480438185
-0.6071987480438185 x 100 = -60.72%