This data is derived from Redfin, See the link below for more details and the top 50 list:
Top 10:
1. York, PA
2. Reading, PA
3. Lancaster, PA
4. Evansville, Indiana
5. Seattle Washington
6. Cincinatti, Ohio
7. Grand Rapids, Michigan
8. Wichita, Kansas
9. Harrisburg, PA
10. Fort Wayne, Indiana
23. Allentown, PA
32. Scranton , PA
36. Montgomery County, PA