The CEF site also breaks the yield down into the income and distribution yield component.

FORBES: Profit Now From January Effect

Of course, if you are investing through a tax-favored account, there is no state tax, and this component of your yield spread is gravy.

FORBES: Magazine Article

It concludes that the three most important determinants of the dollar's swings against the euro (or against the euro's component currencies before 1999) have been relative expected growth rates, bond-yield differentials and net equity portfolio flows.

ECONOMIST: The dollar