Expected years of being single without romantic partners

I've been working on the rise in non-partnered singles, which is my project next academic year. I'm thinking about estimating expected years of being single without romantic partners, and compare the trend between Japan and US.

Figures below are tentative results for the Japanese data. Age specific first marriage rates are calculated from the vital statistics and the information about dating was obtained from the Japanese National Fertility Surveys（出生動向基本調査）. Since the timing of dating is not collected by the JNFS, I used the Sullivan method to estimate person-years of being single without dating partners. I used the synthetic cohort estimation of the single decrement life table. The full information of dating is not yet publicly available for the latest JNFS data in 2015, so the trends in dating in this period are missing in the current estimation.

The first two graphs show expected years of being never-married and never-married without a dating partner. Unsurprisingly, the trends show that men and women are increasingly expected to live longer as single and the expected years of being single without dating partners also increased over time.

What is striking to me was the last figure that shows the proportion of being without a dating partner among the expected years of being never-married (to put it simply, the estimate is obtained by dividing ex(non-partnered) by ex for each sex, age, and period). Individuals are more likely to stay single without any dating partners in recent years, especially for women.

These results are all based on aggregated data which is publicly available from the e-Stat, a portal site for Japanese Government Statistics.

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