There are 24 different races at which you can qualify for Kona, but you still have to be good — really good. The most difficult part of the Hawaii Ironman is getting in. The numbers prove it.

Each year, more than 90 percent of those who start the world’s most famous triathlon finish it. But only about 5 percent of those who try to get to the starting line — that is, who compete in an Ironman qualifier or enter the Ironman lottery — actually make it there. It’s easier to gain admission to Harvard.

It wasn’t always like this. Take the example of Steve Sokol, 47, now a fitness consultant based in San Jose, Calif. Sokol was one of more than a million people who read Sports Illustrated magazine’s coverage of the second-ever Ironman in the fall of 1979, and he was one of about 100 people who came away from it bound and determined to participate in the next Ironman. So he did.

For this was back when the hardest part of the Hawaii Ironman was the race itself.

"All I had to do was fill out a registration form and pay the entry fee — oh, and provide my own support crew, because they had no aid stations back then," Sokol says. "There were no qualification standards or requirements. They didn’t turn anyone away."

Sokol completed the race, which was then held on the island of Oahu, in 14 hours and change. In addition to there being no aid stations, the entire course was open to traffic, there were no sponsors, and no prize money was offered. About 120 athletes participated that year.

When Sokol returned to compete in the ’81 Ironman, it was already showing signs of becoming the coveted rite of passage it is today. Now held in Kona, where it remains today, it accommodated a field three times the size of the previous year’s. The course was closed, aid stations were available, and the race was even televised on ABC’s Wide World of Sports.

"Everything changed that year," Sokol says. "It went from an event that a few crazies had heard of and tried to complete, to an actual race."

But that was only the beginning. A few years later, the Hawaii Ironman capped its field size at 1,500, which required the establishment of a qualifying system. In 1983, there was one qualifier. In 2002, there will be 24 Ironman qualifiers held around the world — 17 Ironman-distance events and seven half-Ironman events. In each of these events, qualifying slots are parsed among a variety of separate divisions, including professionals, five- and 10-year age groups for either gender, military, and so forth. Your chances of earning one of these qualifying slots depends to a great extent on your particular competitive division, but there’s such an overabundance of athletes in each of them that they’re all highly competitive.

The relative difficulty of qualifying depends also on the specific event you choose. At the larger, more established events like Ironman Austria, there are more than 30 athletes per qualifying slot, whereas in smaller, newer, and more out-of-the-way races like Ironman Malaysia, the odds are considerably better.

The immense growth in the popularity of Ironman racing has not only increased the sheer volume of individuals seeking a fixed number of qualifying slots, and the number of qualifying events among which these slots are distributed, but it has also produced faster and faster Ironman triathletes, which makes qualifying difficult in another way.

For example, at this year’s Ironman Switzerland, the slowest competitor in the male 30-34 division to earn a qualifying slot completed the race in 9:19:50.

Indeed, these days, the athletes competing in the younger age divisions in Hawaii are essentially sub-elites, who train almost as hard as the pros and are only slightly less genetically gifted.

In fact, says Hawaii Ironman race director Sharron Ackles, "We still have age-groupers placing in the top 15 overall almost every year."

Yikes!

If Steve Sokol was the typical Ironman participant of yesteryear, Bill Reeves, 33, of Durham, N.H., is the typical Ironman participant of today. A former collegiate swimmer, Reeves teaches high school math because the teacher’s lifestyle affords him plenty of time to train, which he does 20 or more hours each week, year-round. He strives to qualify for Hawaii every year, and he always does, so that’s one less Ironman slot for you and me. (His Ironman-distance PR is 9:12.)

And it’s only getting tougher. Believe it or not, some of the qualifiers now have their own qualifiers. For example, Australian residents who wish to participate in the Hawaii Ironman without leaving their home country to qualify must first qualify for Ironman Australia at one of several designated half-Ironman events held Down Under, and then earn a slot at the full distance.

Ironman Lake Placid also has instituted its own qualification system, and according to Ackles, "It’s not unlikely that we’ll see more of this kind of thing in the future."

Thankfully, there will always be the lottery. In keeping with the Ironman founders’ original vision of the race as a challenge that anyone could do, the Hawaii Ironman reserves 200 slots annually for winners of a random drawing. Contrary to popular belief, it’s actually slightly easier to get to the Ironman starting line this way.

In 2001, for example, about 3,400 individuals applied, yielding a success rate of just under 6 percent. The success rate for those trying to sign up for Ironman Florida, by contrast, was about 5.5 percent.

The odds of being accepted into Harvard University’s freshman class, for your information, hover around 10 percent.