High yield means low prices. If a bond is seen as strong you have to pay 97 cents for a dollar return, give or take, or even more, for "security".
Highest yield means fewer people have confidence in the government's ability to pay back the loan (the bond).

Smart people get confused, so don't fret...
Look up inverted yield curve and you will get a good schoolin'.

Greek bonds have a huge return (OVER 500 percent) because people demand a lot of interest from a suspected deadbeat.

Peace and Faith