Absentee Owner 55+ List

[Chris Eley]

Hey BP!  I'm working on doing my next mailing campaign and wanted to try to improve my list of absentee owners by adding owners that are 55 and older.  Any ideas on how to generate this list?  I've tried adding the age criteria to Listsource, but it looks like the majority of the leads are filtered out when doing this (most leads are in the "unknown" category).  Has anyone successfully created this list or something similar? 

Thanks in advance!