So many people have realized that it is possible, and they keep trying to improve the amount. Of course many people doing are engineers and the like, so it isn't as difficult. Still, there are normal earners that do it. If you are married with two incomes, live off just one and the other spouses income is for investing.

Here is a chart that shows you how long you have to work with each savings rate percentage. 50% is about 17-18 years.