Any reason why all the US holidays don't show in my calendar.

Here's my settings.

Tools/Options/Calendar Options.../Add Holidays.../United States is checked

Okay, so where else am I suppose to look so all my US holidays showed up in
my calendar.

P.S.
I'm starting to feel that Microsoft's products are goind down hill, at least
for Office 2007, Vista, and Visual Studio 2008. I have all three of this
products and they have to much problems (bugs).