It is a fact in the sense that the average stock market return over the course of the 20th century was ~10%. Of course, as every prospectus tells you, past performance is not a guarantee of future results, but what else are you going to use as a baseline?
Disclaimer: I have limited experience with anything finance, my profession is programming.
My understanding is that 10 years ago was a stock market crash(2008), and since then we've been in a historic bull run. My understanding is that it WILL crash again (obviously), we just don't know when. But the stock market has always been like this, cycling between bull/bear runs.
Wouldn't it make more sense to use a larger dataset that isn't just a bull run? Maybe the last 25 years or whatnot?
