Duchess Corporation wishes to determine its cost of common stock equity, r$\_$s$.$ The market price, P$\_0,$ of its common stock is $$50$ per share. The firm expects to pay a dividend, D$\_1,$ of $$7$ at the end of the coming year, $2013.$ The dividends paid on the outstanding stock over the past $6$ years $(2007$ through $2012)$ were as follows:

Year Dividend

$2012$ $$3\mathrm{.}60$

$20113\mathrm{.}62$

$20103\mathrm{.}47$

$20093\mathrm{.}33$

$20083\mathrm{.}12$

$20072\mathrm{.}60$

Using the constant growth model, what is the cost of common equity financing?