ChrisWhiteside.ca

Below is the chart showing the annual returns of the S&P500, sorted Highest to lowest, since 1950. Only 6 years fall between 5-10%. What this suggests is that very few years are "average".

To follow up on another post, gross domestic product (or GDP) is highly correlated to earnings, which is subsequently tied to index performance. If you break it down it seems simple, a strong economy leads to strong businesses which leads to strong stock performance.