-82% is the change from 639 to 115
Calculation steps:
[( 115 - 639 ) ÷ 639] x 100 = -82%
Formula
Percentage change = [(115 - 639) / 639] x 100
Subtract the new number by the original number
115 - 639 = -524
-524 ÷ 639 = -0.8200312989045383
-0.8200312989045383 x 100 = -82%