ding ding ding!!! I was just about to chime in about that. Are these stats accounting for spouse and children and adults in school/military at the time? I'd be curious to see how the numbers break down.
Also of note is that when you do calculate in Spouses and children, they still had insurance because it was less common to "only insure yourself" (I have no data to back that statement up).
Data aside, that is not a logically true claim: in 1980, I had health insurance... through my mother's employer.