In the course of being interviewed by a reporter from Associated Press about the new SSA list, she mentioned that
Mia was extremely popular in Texas and Arizona in 2005 on the state-by-state lists and wondered if that was a Hispanic phenomenon.
After a little Googling I discovered that the probable reason for this is a telenovela called
Rebelde which featured the young Mexican actress Anahi in the chief female role of
Mia Colucci:
http://www.alma-latina.net/Rebelde/Rebelde.shtml
Thought those of you who like to track pop culture influences on names might be interested.