Michael Blowhard, quotes Modern Marvel series saying that the average bra size in US has increased from a 34B to a 36C since 1991

In 1991, the average bra size in the U.S. was 34B. Today, it's 36C.

Now, everytime you hear of average bra size, it seems like an oversimplification of factors that have to be known before just saying "wooweee, America has bigger boobies!".

There is the fact that there are more obese people in America increasing dramatically many averages, there's also a better bra fitting culture teaching women to wear the correct bra size, which may times tends to be a band size smaller and bigger cup size.