Where can I find or purchase data to compare the number of renters to
the number of home owners in U.S. metropolitan areas?

The data can come from either public or commercial sources.  The data
must allow me to calulate the ratio of renters per capita and the
number of home owners per capita in a metropolitian area.  The data
must allow me to calculate this ratio for at least the 10 largest
metropolitian areas, namely:
New York
Los Angeles
Chicgao
Houston
Philiadelphia
Phoenix
San Antonio
San Diego
Dallas
San Jose

The data must be less than 12 months old.  Ideally, the data will be
historical (1 to 3 years worth) allowing me to calculate trends in the
ratio across time as well as geography.