You can go toTrulia Stats & Trends and figure out how much the property values have declined in your area or visit sites such as Zillow.com for sales statistics if you want to do it yourself. I haven't done it myself but I understand you can go to the County Assesors Office website and that they will help you as well. Or, you can contact a real estate agent in your area and ask for help. Zillow is pretty good to get recent sales and you will just have to see what compares to your house. If you would like you can email me at firstname.lastname@example.org and I will email some comps for you.