The average woman's bra size in the USA and America is 34DD which is larger in size than over 20 years ago.
Over 20 years ago the average USA bra size was a bit smaller.
The average bra size over 20 years ago was 34B which is a pretty big leap in size over 20 years later as it seems that as time goes on woman are getting bigger breasts.
Or the woman is at least getting bigger breasts due to breast implants and other plastic surgery for the breasts to increase the breast size.
The inflated breast cup sizes, plastic surgery, and the rising obesity rate are all causes of increased bra size.
My bra size though is 34 B which is big enough for me and I don't ever plan to have any plastic surgery or breast implants to increase my breast size.
I like my breasts the size they currently are.