At relatively low returns, you can double or even triple your money over long periods of time through compounding.
A good way to gauge the performance of your investments is to measure its growth next to Standard and Poor's 500. This is a commonly used barometer to measure investments against.
When calculating your real returns, it is important to ask 2 questions:
1. How much of a tax bite was taken out of your investments?
2. How much did inflation reduce your principal's buying power?