I was surprised that I read this year their home games were 86% sold out. This is bolstered by all the northern snowbird hockey fans showing up in droves though.
I've been a TB Lightning fan since 1992 and their fan base has been growing since they won the cup in 2004--to the point were every game has been a sellout for the last 3 years or so. The downside is ticket prices have skyrocketed for those of us who aren't season ticket holders due to resellers.