-66.82% is the change from 639 to 212
Calculation steps:
[( 212 - 639 ) ÷ 639] x 100 = -66.82%
Formula
Percentage change = [(212 - 639) / 639] x 100
Subtract the new number by the original number
212 - 639 = -427
-427 ÷ 639 = -0.6682316118935837
-0.6682316118935837 x 100 = -66.82%