FYI: The equity risk premium is the academic definition of the idea that stocks should outperform the risk free rate over the long-term. The risk free rate to be used is up for debate, but using the 10 year treasury bond as a proxy gives us a historical equity risk premium of about 4.5% per year since the late-1920s. This means that the S&P 500 has outperformed government bonds by that amount, on average, in that time.
Regards,
Ted
http://awealthofcommonsense.com/2016/09/how-interest-rates-affect-stock-market-returns/