https://link.springer.com/article/10.1007/s40806-018-0169-1

  • Evidence from two independent studies indicated that about half of the singles in our samples were involuntary so.

  • If we assume that about 30% of the adult population is single (see Pew Research Center, 2005, 2013) then, about 15% of the adult population is expected to be involuntary so.

  • Study 1: Men were 1.97 times more likely than women to be in the "I find it difficult to attract a mate" than to the "I am between relationships" category. Not replicated in Study 2 [perhaps due to the inclusion of "Other reason" category?—seems convenient for the researchers who predicted no effect of sex because of their incomplete hypothesis].