Gallup: Underemployment at 20.3% in March

Gallup says that the rate of underemployment in the U.S. rose to 20.3% in March.

Why is it that Gallup's unemployment number is 10.4%, while Obama tells us it's only 8.8%?

*Update*
The link above is corrected. Sorry, the numbers are now only 19.3% and 10.0%. But my rhetorical question still stands.