Good question, but i'm not sure you can give it numbers exactly.
But for my part, i'm well aware that the period between voting for leaving, and actually leaving is going to be tough. The financial markets don't like the unknown and it's clear that there is going to be 2 years of that.
That being said, it's a decision from me that long term will be better (just making clear, better is not 'wealthier'), so it's something than can probably only be answered in 10 years or more. And then, you'd have to look at our prosperity, and compare with that of the EU. You also need to look at what the EU is then. In 10 years the union may well look and behave different. For better or for worse, as lets be honest, we don't know where they will be, and if they will change it's usual course now they've been given a bit of a wake up call. Ironically, it could be the catalyst for real change in Europe. I'm not so sure, but it's still a possibility at this stage.
At the moment, Britain unemployment rate is very good, and been improving year after year. I think that will be a key indicator in 10 or more years. But that would have to been seen in terms of a comparison with a number of the stronger EU economies.
It's not going to be a case of one thing.
So in 10 years time, what's our unemployment rate. How does that fit in with the EU. And what states is the EU in (politically as well as financially) and just how acceptable is that.
Here's a current comparison of the unemployment rates.
http://ec.europa.eu/eurostat/statist...April_2016.png
At the moment though, far too many of the EU countries in the eurozone are straddled with large debts, there's no real plan in place to deal with that. The EU as a financial market is going to be under alot of pressure at the same time we're working towards and in the early stages of leaving. I really can't see a situation where our econemy stalls and the EUs takes off. We may well be slightly down on where we could be if we stayed in the EU and out the euro crises. But that's perfectly acceptable.