In the UK;
- 22.2 million dwellings
- 68% are owner occupied
- 15% are rented
- the rest are LA and HA
- 81% are houses, 19% are flats
- 90% of owner occupied are houses
- Approx. 55% of owner occupied properties have a garage, 25% have off street parking and 20% have either no parking or inadequate street parking.
- Approx. 25% of private rented have garages (I think it might be less than this but I can't tell from the graph)
So out of the 22 million dwellings, approximately 8.3million (22.2mil * 0.68 * 0.55) are owner occupied with a garage (37%)
https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/6703/1750754.pdf
People can also put chargers outside of the garage, but unfortunately the data only shows "off street parking", not whether or not it is suitable for charging electric cars
The only other thing would be the size of garages. I live in a flat. I have a garage. The garage is both too small for any midsize+ car (I have a Mazda3 and it doesn't fit), and it does not have power supply to it, as it is in a separate block. So out of the 37% owner occupied with garages, how many would actually be able to have a car in there able to be charged? (although I suspect the amount that couldn't go by Tesla architecture is very small, it is bringing that 37% down even further).
I do also agree about cost. I can get a Mazda6, 2.2l Diesel Sport for £27k, compare that with the above Mitsubishi iMiEV. Which would you choose!?