This is a question I'm almost always asked whenever someone sees my car and I have, up 'till now, not been able to answer. Fortunately I've ways of dealing with big data and have managed to beat it into submission...
Given there might be a bit of interest in other early Fords I include a little on that here as well. Note that in attempting to be as accurate as possible there are some potential contamination issues if one is after data on purely original cars. Such issues include hot-rods and other specials, but I've attempted to cover that will explain as I go along.
There are 683 Ford vehicles on the New Zealand register built earlier than Dec 31 1927:
Earliest is a red 1903 Model A, first registered in NZ Sept 1903 with the country of origin listed as United Kingdom! There is also one Model F, and one Model N.
Latest is a black 1927 Model T 'convertible', first registered here in 1983. However I think this is not an original car because the motor serial number isn't correct, and it's listed at 4.4L.
The earliest Model T is a red 1909, first registered here in Jan 1909. Engine number is 671.
Latest original Model T is a cream 1927 Tourer, first registered in Gore, NZ, on 3rd Dec 1927.
From now on it gets difficult because the model data is 'free field', which is to say the model could be a Roadster, Tudor, Tourer, T, Model T, T Bucket, Beauty, New Beauty, Truck, Torpedo, 1 Ton and several others (including variations of those already stated).
However if I specify we're only looking for those vehicles with an engine capacity of less than 3L, and which must contain 'T' within the model I find that - somewhat surprisingly - we've got 417 road-registerable Model T's here.
To add a little more detail:
Just 132 of the 417 vehicles claim to have been first registered in New Zealand prior to 1928. This increases to a possible total of 260 if we take into account the full range of 're-registered' T's (which could mean those left in a barn for 50 years, discovered and put back on the road with no specific idea of the original registration date). The remainder are either unknown or they were imported into the country later than 1928.
In the past 30 years we have imported 65 Model T's, I'm not sure how many we exported.
Of all of the original Model T's 157 are black, 78 are Red, 72 Green, 53 Blue and the remainder a mix of yellow, brown, cream, white, purple (yes!), orange, silver and grey. If anyone really wants to know I can drill down for the exact numbers of these other colours.
154 of the T's identify as convertible (Tourer, Roadster), 154 also as saloon (Fordor, Tudor), 24 are Utilities, 17 are Light Van's, there are 37 Trucks, and 24 are a 'Sports Car' (which apparently includes a model known as a 'race-a-bout'!).
And finally, numbers by year:
1909 1
1910 2
1911 7
1912 12
1913 25
1914 17
1915 33
1916 4
1917 8
1918 16
1919 9
1920 4
1921 7
1922 10
1923 70
1924 31
1925 27
1926 92
1927 36
Obviously this is specific only to NZ, and we do have a fairly high vehicle ownership per capita (higher even than the U.S.), however one could possibly extrapolate to some extent for other similar countries and scale as appropriate for population

As a very rough example: statistically we have one Model T per 11511 people. The U.S. vehicle ownership per capita is 97% of New Zealand's so, for current population levels, there should be approx 27900 usable Model T's in the U.S. However, just to muddy the waters, our more traditional source of vehicles has been the U.K., and obvously the T was manufactured in the U.S., so most likely that'd skew the actuality somewhat towards the US number being higher. I've seen numbers around 50,000-60,000 alive and well in the U.S. which at approx double the extrapolation doesn't seem unreasonable, but could be excessive.
For the U.K. I get ~3200 Model T's in total. This may be skewed a little the other way in reality since the U.K. had a thriving vehicle manufacturing industry (we relied totally on imports), so let's say at a rough guess just 2000 examples still exist there today.
To conclude, if we were to consider all the likely countries of the world to have usable Model T's, based on this very crude measure and a lot of hand-waving and much angst, it suggests there may be no more than 70,000 Model T Fords remaining out of say 15,000,000. If at all accurate this represents a 4.6% survival rate - not bad, but it maybe a little high?
If one utilised just the NZ figures and did very little 'correcting' (which may not be all that unreasonable, given we've actually imported a number in later years) then this drops to say ~38000 remaining vehicles in the world, at a 2.5% survival rate...
What say you
