As shown by the black bars in the chart, DNF rate for qualifiers was 4.5% in 2010; DNF for lottery winners was less than 2%. However, part of the explanation is the dramatically higher rate of lottery winners who don't get to the starting line -- more than 9%. Naturally: only those lottery winners who are really ready to race take the long flight to Kona.
Ironman Kona: Qualifiers vs Lottery Winners
The path to racing the Ironman Triathlon World Championship in Kona is an extremely difficult one: either you race at a nearly elite level to qualify (about 1720 athletes in 2010), or you face increasingly long odds of winning one of 200+ lottery slots each year. It goes almost without saying that, in general, the qualifiers will race Kona faster than the lottery winners. But here's something you might not have expected: if a lottery winner gets to the starting line in Kona, they are more than twice as likely to finish the race.