The S660 roadster has been a success so far for Honda. (At least, that is, insofar as a niche-market sports car limited to the Japanese Domestic Market can be considered a big seller.) It just hasn’t resonated with the customers that the company expected.

Honda revealed the S660 in concept form at the Tokyo Motor Show nearly two years ago, and subsequently put it into production. The convertible Kei car pays homage to models like the S500, S2000, and Beat. It packs a tiny 660cc three-cylinder engine mounted amidships and driving the rear wheels. Despite its connection to past models, the S660 features an entirely modern design that, along with its low price, was expected to appeal to younger buyers. But while Honda has already sold out all 8,600 examples it’s slated to build this year, a surprising 80 percent of them have been snapped up by customers over the age of 40 who are mostly buying them as second cars.

The development is not entirely isolated. As Bloomberg points out, the number of licensed drivers in Japan “under the age of 40 has fallen 46 percent over the last 13 years.” Those are rather startling numbers that dwindle the market down for youth-oriented vehicles like the S660. Honda is expected to begin taking orders for next year’s allocation of S660s in October. At that point, the company anticipates the average age of its customer base will drop. But with fewer young drivers on the road in Japan, it shouldn’t expect it to drop by much.