:between 1920 and 1929 on average how much did stock prices increase

Look at the chart that I have attached. The low point was between 55 or 60 to 381. When you look at something like Bitcoin, that doesn't look like it was very much, but there are two things that you really have to keep in mind. 

1. Most people had only about 10% of the price of the stock covered. What that means is that if a stock cost 100 dollars, most people had only 10 dollars holding it down. The rest was put up by the bank. The market was doing such crazy things that I don't even think the banks checked into your credit. The stock was holding down what you owed. The bank only got its share when you sold. Preposterous!!! It sure was.

2. The second thing is that the numbers I've given you were the Dow Jones Industrial Average. That's the cream of the cream on the NY stock exchange. Who knows what was going on with companies that were not that big. They were what the economic writers would have called "Good Speculations," which translated into "go mortgage your house, sell your furniture, back up the truck (and then sell it too) and buy xzy. You'll never be broke again." 

That by the way is why bitcoin and all its relatives is so dangerous. 

By voting and keeping it lowkeyv