-34.7% is the change from 977 to 638
Calculation steps:
[( 638 - 977 ) ÷ 977] x 100 = -34.7%
Formula
Percentage change = [(638 - 977) / 977] x 100
Subtract the new number by the original number
638 - 977 = -339
-339 ÷ 977 = -0.34698055271238487
-0.34698055271238487 x 100 = -34.7%