-34.39% is the change from 974 to 639
Calculation steps:
[( 639 - 974 ) ÷ 974] x 100 = -34.39%
Formula
Percentage change = [(639 - 974) / 974] x 100
Subtract the new number by the original number
639 - 974 = -335
-335 ÷ 974 = -0.34394250513347024
-0.34394250513347024 x 100 = -34.39%