It seems to be very uncommon! I go a few times a day and I've only seen non-native fruit twice. It seems the islands are inclined to give you your own native fruit and flower by default, with something else being about as common as the Bamboo Island.
(Though in my case, I haven't seen the...
A friend pestered me until I downloaded New Leaf!
I'd been reluctant because I found a lot of villagers creepy and wasn't sure about a game that would penalize me for not playing every day... but I thought Isabelle was cute and my friend had been trying to get me to play awhile, so I finally...
I got Deirdre (second fave!) and Goose (never had him before but I like him a lot!)
And I have Walker, Celia, and Piper coming in - all Villagers I've never had before. ^^