All the code is in the same repository as R Markdown.
SPY / VFIAX / S&P 500 has a CAGR 4.9% from Nov 2000 to Nov 2016.
"The average 30-year rolling total return for the S&P 500 starting with 1926, is 2,478% or 11.21% annualized (geometric mean). There were several 30-year periods that had annual returns between 8% and 10%."
Having said so, past returns don't guarantee anything for the future. They might give you an indication though.
Edit: Here's  a better (?) graph of the S&P 500 with the 30 year rolling returns, inflation adjusted and dividends reinvested. Source