I'd be curious to see a more detailed breakdown on reasons for No. E.g. natural death, assassination, impeached and removed, 25th amendment (does this even count), other?

To me, none of these seems anywhere near likely enough to justify the current No percentage.

@MichaelMcMullen A temporary transfer under the 25th amendment (for example, like what Bush and Biden did for their colonoscopies) would not count here.

@MichaelMcMullen For a generic 80-year old American male, the life expectancy is 7.74 years, as I understand the table (https://www.ssa.gov/oact/STATS/table4c6.html).

@MichaelMcMullen It may be interesting to compare with: https://manifold.markets/BTE/will-the-next-person-elected-us-vic

@burkh4rt The 25th amendment transfer doesn't have to be so temporary though. If a president in their eighties became very sick but didn't die, the VP could potentially become acting president for the remainder of the term which could be years.

@burkh4rt Yes, the life expectancy of an average eighty year old is less than eight years, but the eighty year olds in question have above average health for their age, and the president has access to better medical care than the average eighty year old.

@MichaelMcMullen This is an interesting edge case, and not one I imagined as very likely when writing the question. For the purposes of this question, I think if the VP were "acting as president" in a full-time manner under the provisions of the 25th amendment at the end of the term, then it would be fair to say that the president was not "serving" at the end of the term.

@burkh4rt The reason I phrased this question in terms of the president and not the VP was to avoid any sort of Gerald Ford-style edge cases.