property value increase records

Any idea where I might get a record of how much home values increased in my area over the past year?
Bought my home 2 years ago with an appraised value of $180K.
One year later I had to have it reassesed for refinancing and it was at $198K.
I need to borrow some equity but they are using the $198K figure.
What can I assume the increase to be over the past year? 10%?
Is it worth having it reappraised?
Is there a link that will show by zip code home value increases?

Home Price Check may have what you’re looking for.

You might find this useful:
http://www.co.hennepin.mn.us/vgn/portal/internet/hconlineservicemaster/0,2333,1273_1716_100007320,00.html