(I won’t say the 19th century, because pedants will insist that ended on December 31, 1900.)
This is a challenge for statistically-inclined LGMers.
As of today, there are still six people alive with verified birthdates prior to 1900. All are women. Four are Americans, the oldest is Japanese, and the youngest is Italian.
116 years 244 days
116 years 123 days
115 years 165 days
115 years 121 days
115 years 103 days
114 years 340 days
Per social security actuarial tables, an American woman has a life expectancy of .84 years on her 115th birthday, and a 72.95% probability of dying within the next 365 days. The comparable figures on her 116th birthday are .77 years and 77.33%. For her 117th birthday, they are .71 years and 81.82%. For her 118th birthday, they are .66 years and 85.90. For her 119th birthday, they are .60 years and 90.20%. I don’t have comparable figures for Japanese and Italians, but let’s assume they’re the same.
On what future date is there a 50% probability that there will no longer be any people alive who were born in the 1800s?