50% rate of infection?
According to this ScienceDaily release, half of all Swedish 20 year olds are "carriers" of C.Pn.
Full text of the dissertation is available, but it's 100 pages long, and I haven't find the citation for that "50% carriers" factoid.
Loads of good, good stuff about the plaque formation and vessel damage that was described in The Potbelly Syndrome -- worth a look. I'll look harder for the citation later, but it's 4am, and I have rested enough to sleep some more, so that's my next job.