One of the best-known trends over the last few years has been the increase in the number of models on sale.

As new niches have emerged, manufacturers have rushed to fill them.

One might logically assume that as the number of models in each manufacturer’s range increases, the dependence of a manufacturer on any one particular model would go down. Logical, but wrong.

As the table shows, the dependence of some manufacturers on one single part of the market can be scary. For example, virtually three-quarters of Fiat’s sales are in the citycar segment, while close to two-thirds of Alfa Romeo sales are in the lower medium segment.

At the other end of the table, it is noticeable how much more broadly spread are the three German premium brands.

All of them have no segment taking much more than a third of their sales. That is one of the factors behind their success.

Of course, it is too simplistic to say that manufacturers who have their sales spread across a number of segments are necessarily doing better than those whose sales are more concentrated.

Toyota has a broad spread of sales, but none of its models is exactly setting the market alight right now, though it is hoping the new Yaris will do just that.

However, it does point to possible issues for the future. For example, the Nissan Juke is doing extremely well, but it means that over half Nissan’s sales are in the supermini segment and a further 42% are in the lower medium segment.

That means its two blockbuster products – the Juke and the Qashqai – account for a very big proportion of Nissan’s current success. It puts a lot of weight on the team developing the Qashqai replacement.

The interesting thing is that so many mainstream manufacturers’ attempts to spread their model range have had limited effects.

For example, Volkswagen has hugely expanded its model range in recent years to reduce its dependence on the Golf.

Despite the fact that many of its new models have done well, 42.9% of its sales still come from the lower medium segment, the vast majority of which are the Golf.

It seems that, despite all the shiny new models, the buying public can still be quite conservative. Shifting the centre of gravity of a car company is a very long-term project – and these fig-ures show why it is so much easier to announce a change in model strategy than to actually achieve it.