Going back to the original post by della, I'm not sure if models are getting smaller. I can't imagine anyone thinner than Twiggy, the supermodel of my era. The only thing large about her was her eyelashes. No, I just think it's more women getting larger.
Women are getting larger, there's no doubt about that. But Twiggy was an anomaly. That's why she was called Twiggy. Nowadays, models who are Twiggy's size just go by whatever their name is, because they aren't unusual.
Here's an ABC News article saying that plus size, once considered sizes 12 to 18, nowadays might include size 6.
The only time I've ever worn size 6 in my adult life was when I was at my very thinnest.
In
The Devil Wears Prada, one running joke is that the dragon-lady NY magazine editor calls Anne Hathaway "the fat girl." She's said to be a size 6 (though I bet the real Anne Hathwaway is smaller than that).
In 1990's
Pretty Woman, Julia Roberts was a size 6.