Hockeydb has yearly average attendance figures for Phoenix here:
http://www.hockeydb.com/nhl-attendan...h.php?tmi=7450
According to their figures, attendance averaged at least 13,000 each season, and usually hovered around 15,000, until the team filed for bankruptcy in 2009. There was a substantial increase when the team moved to Glendale in 2003, which makes sense, actually. You would expect to draw better in a building that was actually designed for hockey and has unobstructed sight lines from all the seats.
What I can't find as easily is
paid attendance or the average price of the tickets sold. How many of the pre-2009 tickets went to paying customers, and how many were used to paper the house, is not information that people seem eager to disclose.