The ACE study mentioned ([0]) suggests that about 2/3 of people have 1 or more ACE, but after looking at the definition of ACE they used, it appears to use a significantly weaker definition of trauma than even the expanded one given explicitly in the article: it includes having a parent with a mental health issue, having a chronic health condition while young, or being chronically separated from a parent (due to eg divorce).
Further, it looks like there is quite a bit of clustering: people with ACEs that qualify as classic traumas tend to have several.
Perhaps trauma is much more pervasive than I thought, but it looks to me like the definition of trauma was changed quite significantly to make the claim hold.
[0] https://www.aap.org/en-us/Documents/ttb_aces_consequences.pd...
There is more info on the wiki page here as well:
[1] https://en.m.wikipedia.org/wiki/Adverse_Childhood_Experience...