-35.32% is the change from 988 to 639
Calculation steps:
[( 639 - 988 ) ÷ 988] x 100 = -35.32%
Formula
Percentage change = [(639 - 988) / 988] x 100
Subtract the new number by the original number
639 - 988 = -349
-349 ÷ 988 = -0.3532388663967611
-0.3532388663967611 x 100 = -35.32%