I am looking to update the formula used by Benjamin Graham to calculate a stock's intrinsic value. His most recent formula can be found at http://en.wikipedia.org/wiki/Benjamin_Graham_formula.
The formula contains the number 4.4, which was the average yield of high-grade corporate bonds in 1962, which was when this model was introduced.
I am trying to make the formula more relevant and updated via replacing 4.4 with the current average yield on high-grade corporate bonds.
Does anyone know what this number is, or where I can find it?
Thank you for your time. All help is greatly appreciated.