[jonkho]

Lies, damned lies, and statistics. This is old era data. The era when this data is collected is when marriage is overwhelmingly the norm for those generations (the life-expectancy data is collected from the current elderly). People who were single presumably could not get married due to lack of societal fitness (health, wealth or other issues etc). This lack of fitness could very well be co-factors for short life.

Data collected for the next 50 years should be more telling as larger swaths of the population are single regardless of fitness and should reveal more truth.