-34.95% is the change from 990 to 644
Calculation steps:
[( 644 - 990 ) ÷ 990] x 100 = -34.95%
Formula
Percentage change = [(644 - 990) / 990] x 100
Subtract the new number by the original number
644 - 990 = -346
-346 ÷ 990 = -0.34949494949494947
-0.34949494949494947 x 100 = -34.95%