Anshu pointed to this in the comments:
Teenage interest in NHL:
Ottawa 41% follow closely or very closely
Toronto 20% follow closely or very closely
The study also says this about adding teams in order to raise interest:
As a key part of their attractiveness, of course, those new teams need to be competitive and entertaining – shortcomings that have been particularly blatant in the case of the Maple Leafs.
Note that this survey was taken in late 2008 - before Wayne Primeau was added so I'm sure those Leaf numbers are way up now.