Apparently American clothing stores are cutting their plus-sized clothing lines at the moment, even as the average American woman gets larger. Why? Because the mean size isn’t the important one. There’s an excellent explanation here:
…it has to the do with the fact that the distribution of weights is skewed to the right. The costs of production result in a focus toward the modal body size, not the mean or median.
Basically, it costs more to make more sizes. The manufacturer wants to make the fewest sizes to fit the most people. Lots of people fit the small sizes. Large people span a huge range of sizes, so not many will fit each big size. Hence, it’s profit maximising to produce only the smaller sizes.
An interesting corollary is that plus-sized clothing sales are increasingly moving to online retail only. That allows the manufacturer to capture a larger market than they could with a retail store and makes it worthwhile to produce the larger sizes. They also don’t need to keep a lot of stock on the racks, which is a significant fixed cost to the business.