The presidential campaign of Vice President Kamala Harris has seized on Sen. J.D. Vance’s (R-OH) comments regarding childless women, and it makes perfect sense, demographically speaking: Single women are now the most important voter bloc for the Democratic Party.

While married men, married women, and unmarried men all trend at least narrowly Republican, unmarried women overwhelmingly vote for Democratic candidates. Moreover, the proportion of women who have never married has grown from 20% in 1950 to 30% today, while the percentage of women who are currently married has decreased from 70% to less than 50% in the same period. The number of married households with children has similarly declined.