Prevalence of vaginal dryness

Laumann, E.O. et al. “Sexual Dysfunction in the United States: Prevalence and Predictors,” Journal of the American Medical Association (1999) 281:537.

Laumann, E.O. et al. Sexual Dysfunction Among Older Adults: Prevalence and Risk Factors from a Nationally Representative U.S. Probability Sample of Men and Women 57-85 Years of Age,” Journal of Sexual Medicine (2008) 5:2300.

Orgin of natural vaginal lubrication and factors that affect it

Berman, J.R. “Physiology of Female Sexual Function and Dysfunction,” International Journal of Impotence Research (2005) 17:S41.

http://aibolita.com/sundries/15502-physiology-of-vaginal-lubrication.html

Origin of pre-ejaculatory fluid

https://en.wikipedia.org/wiki/Pre-ejaculate

Lubricant sales 1991 and 2015

http://answers.google.com/answers/threadview/id/716392.html

http://www.hopesandfears.com/hopes/now/question/214049-lube-question

Around 50 million U.S. lovers use lubricants

https://www.statista.com/statistics/276824/us-households-usage-of-personal-lubricants/

Indiana University study of women’s feelings about lube

Jozkowski, K.N. et al. “Women’s Perceptions About Lubricant Use and Vaginal Wetness During Sexual Activities,” Journal of Sexual Medicine (2013) 10:484. 

Women say lubricants make sex more enjoyable

Herbenick, D. et al. “Association of Lubricant Use With Women’s Sexual Pleasure, Sexual Satisfaction, and Genital Symptoms: A Prospective Diary Study,” Journal of Sexual Medicine (2011) 8:202.

Herbenick, D. et al. “Characteristics of Condoms and Lubricant Use Among a Nationally Representative Probability Sample of Adults Ages 18-59 in the United States,” Journal of Sexual Medicine (2013) 10:474.

Hickey, M. et al. “A Randomized, Double-Blind, Crossover Trial Comparing a Silicone- vs. Water-Based Lubricant for Sexual Discomfort After Breast Cancer,” Breast Cancer Research and Treatment (2016) 158:79.

Jozkowski, K.N. et al. “Women’s Perceptions About Lubricant Use and Vaginal Wetness During Sexual Activities,” Journal of Sexual Medicine (2013) 10:484.

Laumann, E.O. et al. The Social Organization of Sexuality: Sexual Practices in the United States. University of Chicago Press. Chicago. 1994.