# Calculating returns for a mutual fund with dividends

I'd like to calculate returns for a given mutual fund (in this case, PRWCX from troweprice). When I look at their published performance, it says the Calendar Year Total Returns for 2013 is 22.43% but when I try to calculate that using with a formula (end.price + dividend - start.price)/start.price I get something different.

The price on 12/31/13 is 25.66 (adjusted close is the same), there was a dividend of 1.54 on 12/13/13, the close price on 1/2/13 is 22.56 and the adjusted close is 21.25. If I calculate the return using the close price, I get 0.2056, and if I calculate based on adjusted close, it's 0.28. The fund has an expense ratio of 0.71% (as of 12/31/13) and even if I subtract 0.71% from my results, I don't get anywhere close to 22.43%. Does anyone know what I could be doing wrong?

Also, I'm wondering if someone could tell me how Average Annual Total Return (for say 5 years or 10 years) is calculated.

My goal is to compare returns of this mutual fund to returns based on the S&P500 or individual stocks.

When we hear that the Dow is up for the day, it is not relative to the open, but rather to yesterday's close. Accordingly, I believe the yearly returns for 2013 are calculated, using the yearly adjusted closing prices, as $(C_{2013} - C_{2012}) / C_{2012}$.
I looked up adjusted closing prices on finance.yahoo.com: substituting $C_{2012} = 20.96$ and $C_{2013} = 25.66$ I get 22.42%, which is very close to their published performance.