It's 10% in the market I invest in.I would get away from being too statistical in your cash flow requirements- the investors who make the most money aren't the ones that set their criteria based on the average or median investor, per se.

You might want to look at crime statistics in the areas where you are considering investing.

I began researching various demographics such as population growth, employment rates, job growth statistics, renter-to-owner ratios, etc.

My question is this.. statistically speaking if the owner is up there in age (80's), if I get a 30 owner finance with well enough terms that I would want to keep it and not refinance, they will not be around the whole 30 years...So.... what would happen?

That was not an observation of overall market statistics.

Where is the 5 out of 6 statistic from?

Few things:- Population growth- Job Growth- Landlord friendliness (aka not California)- Diverse industriesThose 4 things take out much of the country, but still do give quite a few opportunities.Sources include Bureau of Labor Statistics, Census.gov, and other organizations like those.

I have no idea how much money you could make in your area but AirBNB might have some statistics for your city/town.Example 2: Reduce your rent from $200/month Version 2Buy a 4 bedroom place that costs you $500/month. 

I don't know the true statistic, but I'd estimate close to 0.5% of homes in Alachua County have had foundation issues addressed. 

Maybe you have family there and visit a few times a year.In other words, I believe, that I can do better in city B, if I have easy access, know it well and have people there, than I could do in City A (difficult to get there, don't know much about it and don't have good contacts) - even though the statistics would say that city A is better to invest.