Damodaran's historical data on 10-year T-note returns (found here) uses the following formula to calculate the 1-period total return on a T-note ($R_1$) given the 10-year constant maturity yield-to-maturity in the prior year ($Y_0$) and the current year ($Y_1$).
$R_1=(Y_0*\frac{1-(1+Y_1)^{-10}}{Y_1}+\frac{1}{(1+Y_1)^{10}})-1+Y_0$
Where can I find a derivation or description of this formula? It seems very odd to me that the only two data points I would need to calculate the total return to a T-note are the beginning and ending yield-to-maturities.