When the average Stock Market Return might be around 10% you gotta know that the returns every year might be very far from the average.
When you look at the years between 1926 and 2014. Then you will see that the returns in these years were from 8% to 12% only in 6 different years. And the rest of that time the “average” returns in the stock market have been much lower or much higher than the 8% to 12%.
Even when the market is unstable the returns tend to be somehow positive in a given year.
As you might expect it doesn’t go up every year but over the time as the years go on you will see that the market has gone up in about 70% of years.