Bra Facts: Wikipedia

In 2006, the average American woman owned six bras, one of which was a strapless bra, and one in a color other than white.[59] In 2012, women owned an average of 9 bras and wore six of them on a regular basis.[58] Consumers spend around $16 billion a year on bras.[58] In the last 15 years alone, the average bust among North American women has increased from 34B to 36C. A number of sources state that about 90% of Western women wear bras, although no authoritative source for this fact is available.[10][60][61] Some women wear bras because of feelings of modesty or because it is a cultural norm and they fear criticism or unwanted attention. Some wear bras because they believe it improves their appearance, while a minority prefer to go without because they find it more comfortable.[62] Some women mistakenly believe wearing a bra helps avoid sagging breasts.[63]

In a cross-cultural study of bra size and cancer in 9,000 women during the 1960s, a Harvard group found 93% wore bras (from 88% in the UK to 99% in Greece), but could not find enough women in Japan who wore bras to complete their study.[64] In a number of cultures, including Europe and other Westernized countries outside the United States, there are fewer social restrictions against sunbathing or swimming topless.[65] A Harris Survey commissioned by Playboy asked more than 1,000 women what they like in a bra. Among the respondents, 67% said they like wearing a bra over going braless, while 85% wanted to wear a "shape-enhancing bra that feels like nothing at all." They were split over underwire bras, 49% said they prefer underwire bras while 49% said they prefer wireless bras.[66]