ice cream causes drownings because you're supposed to wait to go swimming after you eat

I'm imagining a sentence like "the majority of people believe x, but the overwhelming majority believe y." Is it reasonable to assume people who believe y is greater than people believe x?

@HenryLehmann You'd say "Jane is a faster runner than Mary or Jon," and I don't think anyone would reasonably interpret that as them running combined. I think it's just a quirk of the language that you have to know.