Total return includes everything--dividends, capital gains, interest, etc. It is expressed as a percentage of the original net asset value. Assuming that you have re-invested your distributions (see Distributions), then figuring out yield is not that complicated.
(Year-end # of shares * Year-end Net asset value) - (# of shares you owned at the beginning of the year * Beginning Net asset value) * 100 divided by (beginning # of shares * Beginning Net asset value)