What interest rate do you assume sellers have on their mortgage?

[Jose Falconett]

For purposes of an investor doing there due diligence and also for situation where a seller has no clue what they owe, interest rate, monthly payment amount etc.

Since mortgage notes recorded in the public records does not show interest rate only length of mortgage and its principle, what interest rates do you assume a seller would have and how can I learn how to assume this properly?

I've had investors tell me if it was 2010 then likely around 5%. Can anybody instruct me or give me some kind of trend for interest rates!? THANKS

[Jason Hirko]

@Jose Falconett You can find the historical average HERE. It shouldn't vary widely from that. I always just figure $600/month per every $100k financed as a quick calculation. That's 6% APR and you have to go back 15+ years to when loans were averaging more than that, so it's a quick rule of thumb