References are called on nearly everyone. This doesn't indicate anything other than the info you provided SWA was accurate & folks are being called. For the DB to decide on your fate references need to be called. Its always better to have references called vs. no call but as they say....."don't quit your day job over it."
As for numbers who will be selected. SWA has averaged between 1 of 4 to 1 of 3 of those being interviewed who are selected by the DB. There are nearly 300 applicants being reviewed in the DB tomorrow. The % is lower on this group than in those past who have been recommended for being hired. As I stated in another post though, just because the interview recommendation is negative, it doesn't mean the DB has to go along with that recommendation. Being sent for testing prior to the DB is no guarantee one way or the other, as is not being sent is no indication either. It can be overruled based on a many factors, i.e. LORs, other info brought to the attention of the board, quality of flying time, previous jobs, etc. No one is ruled out of being hired before the DB. For those waiting, hang in there.