Taylor,
I think I may not have been clear above:
The TR is the yield + or - the change in NAV.
The point I was making is that if you look at your chart you will see many bond fund that started life at $10 NAV and are still pretty close to that even after 15-20 years.
I was not implying that in any given year the yield would be the TR, just that over time the TR for debt securities is close to their overall yield.
Said another way, we don't buy debt assuming that we will have a return above the yield.
Am I still wrong? :o]
best,
Bill