If you have a specific area of interest a real estate broker can help you to determine which homes in a given area were cash, conventional, fha, va, etc. They can also tell you how much the seller contributed as a concession for the buyer for things such as closing costs. This only applies to houses that were listed through the MLS database and not FSBOs or other such sales. It can give you a general feel for what the trends are in a given area.
Let me know if I can be of assistance to you. One of my areas of expertise is helping investors to identify distressed properties for the purpose of fixing to flip or rentals.
Blessings upon you...