-72.3% is the change from 639 to 177
Calculation steps:
[( 177 - 639 ) ÷ 639] x 100 = -72.3%
Formula
Percentage change = [(177 - 639) / 639] x 100
Subtract the new number by the original number
177 - 639 = -462
-462 ÷ 639 = -0.7230046948356808
-0.7230046948356808 x 100 = -72.3%