Math is hard.
I'll try again. This time I used the
gran-turismo page for reference.
Original tracks - Alsace (2), Blue Moon (6), Dragon Trail (4), Kyoto (5), Maggiore (8), Tokyo South (2), Tokyo Central (4), St Croix (6), Sardegna (6) = 43
Also counted the real life layouts.
Real life tracks - Autopolis (2), Barcelona (1), Fuji (2), RedBull (2), Sarthe (2), Tsukuba (1), Monza (2), Interlagos (1), NBR (3), Willow (5), Brands (2), Panorama (1), Suzuka (2), Goodwood (1) = 27
So a quick count has me at 70 layouts on 23 locations.