Baby Boomers born between 1950 and 1959 mark a turning point.

My unresearched guess is that we got an effort to stop infant and childhood death with penicillin and other medical inventions. That would have upped their mortality and then as they got older newer ways to die was increased. This first generation is dying so we are still figuring out what is a proper average lifespan. It might just be a statistic thing.