It grew over 10 percent last year for total plus size bra sales of $1.9 billion. See more about this at Advertising Age.
Anyone who wears a larger size bra will be glad to know the bra makers are making a special effort these days to create bras that provide real comfort, moisture resistance, great fit and even fashion for bra sizes up to DDD.
Here's some interesting info from a comment at the Fashion-Incubator:
In 1966, the average bra size was 34B. In 1996, just 30 years later, that average has increased to 36C. This corresponds to a woman with an underbust measurement of 32" (give or take an inch either side), a high bust of 36" and a full bust of 39"....The average "mature" woman's bra size is now 38D! It is not at all unusual at all to see junior high and high school students with D, DD and F cups. And yes, they are natural, not augmented. Some of them feel cursed with their breasts, and no wonder. The "teen" bra boutiques are still under the illsuion that fashion bras stop at C cup. I see young women all the time that are wearing bras at least two sizes too small (i.e. a 38C when they should be wearing a 40D) and enduring major discomfort because they are not seeing anything youthful, pretty and supportive, in the places they like to shop.
The photo above is part of the new advertising campaign for the Olga "Christina" plus sized bra. This here is the 'Hollywood extreme cleavage bra' for plus sizes.