IStock Photo 2603601 © Volker Kreinacke

A deadly stampede outside a Wal-Mart store last year, jittery retail executives who began slashing prices weeks ago, and growing online sales are causing some pundits to pronounce “Black Friday” dead.

The level of concern befits a phenomenon that has always had an element of mythology. Yes, millions of people rush to stores early on the day after Thanksgiving. And no, it’s not everyone in the United States. The number of Black Friday shoppers has never approached the number of people celebrating Thanksgiving. Why not?

First of all, a lot of people, including all the people manning the retail stores and restaurants, have to work on the day after Thanksgiving. The odds an adult will plan to go to work on Black Friday are 1 in 5—20% of the population. Another 40% (1 in 2.5) plan to just stick close to home. That leaves 40 percent of the population venturing out to shop or visit relatives or go to see New Moon or Ninja Assassin.

And that breaks down as you might expect. 1 in 8.33 choose the retail rush. The same number goes to visit relatives. Every teenage girl (this figure may be slightly exaggerated) opts for the hunks with fangs.

There are two pieces of Black Friday mythology, however, that stand up to scrutiny. The first is shoppers’ eagerness to get the best bargains—or at least the best parking spaces—by showing up early: 1 in 1.75 (57%) shoppers will leave the house before 7 a.m. to get a jump on Black Friday sales.

The second is that among those who shop, the clamor for the hottest items can be fierce. This year, that could mean a lot of people racing through the maze of a big-box store in pursuit of a stuffed hamster (psychology professors everywhere may be competing for the stores’ security tapes). The Zhu Zhu Pet, a battery-powered hamster with accessories galore, is already in short supply.

Capitalizing on retail shoppers’ rare willingness to embrace unusual hours—and spreading the crowds—some stores are making the 7 a.m. crowd into late arrivals. Wal-Mart and Toys R Us will both open their stores at midnight on Friday. One hopes this works, because the odds an accidental death will be due to being crushed by a human stampede are 1 in 8,824. And that’s no myth.