One of the strengths of the racing industry is that the number of grassroots racers has always been far greater than most people can imagine. PRI magazine was the first to add up all the racers many years ago, and it served as a powerful tool for a lot of racing businesses to take to their bank or investors to prove that there's a heck of a lot more racers than the 33 at the Indy 500 or the 43 at the start of a NASCAR Cup race.

Our first figure was 400,000, including all open wheel, stock car, drag, off-road, road racing, autocross, vintage, Legend and everywhere else someone was running a car in a competitive event. It was a big ballpark figure, plus or minus 50,000, but we've never seen it called into doubt. As the racing...