Percent of Prii in taxicab fleets?

Here's something:

Taxi driver was a driving force in hybrid movement | Climate & Clean Energy | David Suzuki Foundation

At the bottom it says, as of 2009, in Greater Vancouver 1/3 of cabs are Prius.

 

No hard numbers but my impressions of Victoria's current taxi fleet (excluding wheelchair cabs) are:
Mainly Gen 3 Prius liftback
Next would be Gen 2 Prius (decreasing) or Prius v (increasing)
Next would be hybrid Camry
Other vehicles seem rare enough to be noticed if you see one.

I'll look more closely when I'm out on the road

 

There aren't many big taxi queues in Victoria but today I cycled past a queue of 11 taxi cars picking up passengers from a cruise liner that was stopping over in Victoria. Every taxi car was a hybrid. 8 Prius of various types, 2 Camry Hybrids, and one Ford Escape Hybrid.
There were also 2 non hybrid minivan cabs in a separate queue. (They probably specialize in Cruise ships as you don't see many around town)

I've just got back to Victoria from a trip to St John's, Newfoundland where I saw no hybrid taxis at all! I'm not sure why. The taxis there seemed to be basic 2 wheel drive vehicles of various makes so it wasn't the desirability of 4WD in Newfoundland, and gas prices were similar.
There weren't many privately owned hybrids either which is easier to understand as private cars there tend to rust out from salt corrosion years before they would otherwise wear out from mileage. Unless you do a lot of miles per year, like a cab, a more efficient car will not last long enough in that environment to give the financial return it can elsewhere.

 

Here in the GTA there are just a handful of hybrid cars as taxis.

 

Plenty of "Police Interceptor" Crown Victoria Fords available in SoCal for 3000 to 4000 dollars.
Most Airport Cabs are Prius & Prius v now. 10 to 1.
Check out this Old Taxi :::
Toyota Prius Base Hatchback 4 Door | eBay

 

Greater Toronto Area? Grand Theft Auto?

Guessing you mean the first, here's a pic, from about 8 years back. Does look like just regular vehicles. They sure stack 'em up:

 

GTA = Greater Toronto Area

Not much change since then but now we have Uber too.

 

It depends on the market. The Prius has almost disappeared from the NYC taxi fleet. In Hightstown, NJ Prius are about all you see.

NYC is supposed to be electrifying the taxi fleet and Nissan won the contract.

 

Not really true ... plenty of Prius especially v-s are on the road ... and if we count the hybird camry and C-max-es I wold say 20-30% currently hybrid car. The new Nissan contract was invalidated if I am not mistaken by the court.... http://ny.curbed.com/archives/2015/04/01/lawsuitplagued_taxi_of_tomorrow_is_delayed_yet_again.php#more.

Those Nissan NV200s are not hybird nor electric nor handicap accessible (that contract was botched badly) ... originally all cab would be switched to NV200 but now looks like hybrid is an option out of that monster ... so according to that article about 20% expected to stay

I am a daily NYC driver ... also sizeable number in the "green" outer-borough fleet.