From the Calculated Risk blog, a chart showing the FreddieMac mortgage interest rates over time:
This graph shows the 30 year fixed rate mortgage interest rate from the Freddie Mac Primary Mortgage Market Survey®.
The red line is a quarterly estimate from the BEA of the effective rate of interest on all outstanding mortgages (Owner- and Tenant-occupied residential housing).
The effective rate on outstanding mortgages is at a series low of just under 6%, but the rate is moving down slowly since so many borrowers can't refinance because they do not qualify (either because the property value is too low or their incomes are insufficient).
(Again, the source is here.)
The graph is here as a larger jpeg.