The Boghog Number
I've decided that every country has a "boghog number". I'd wager that in most developed countries, the number is around 20-30%, while in the United States, it's around 40%.
The name comes from the Hitchhiker's Guide To The Galaxy series. In one of the books, Arthur Dent pays a visit to a planet called NowWhat, where the economy is based on a product that nobody in their right minds would want to buy:
Trading was mentioned in the brochure. The main trade that was carried out was in the skins of the NowWhattian boghog but it wasn't a very successful one because no one in their right minds would want to buy a NowWhattian boghog skin. The trade only hung on by its fingernails because there was always a significant number of people in the Galaxy who were not in their right minds.
I'd go further and say that you can build a very successful business (or political party) based entirely on marketing to people who are not in their right minds.
Enter Donald Trump...