What mental collapse?

Lord knows I’m no Trump fan, but I have to ask—what sudden mental collapse, cognitive decline, or dive into senility did it mean when he said “94% of the cars in Japan are made in Japan.”?

Without disputing the statistical accuracy of the statement, I’m just wondering what’s wrong with it logically. Doesn’t it just mean that only 6% of the cars driven in Japan were manufactured abroad? and all the rest made at home? How does that comment signify a deranged meltdown?