Fitness trends come and go—remember Jazzercize?—and right now, the half marathon is ascendant. Last year, two million people finished the 13.1 mile race, and 61 percent of those runners were women. Those are huge numbers, and Scott Douglas and Dan Fuehrer at Runners World have more, charting the race's increasing popularity: 
 
 In 1990, there were an estimated 303,000 finishers. That total had more than doubled by 2004. This year's record total of 1.96 million means that, in just less than a quarter-century, there's been more than a six-fold increase in finishers. 
 
 The race seems especially popular in the United States, where 14 of the 20 most well-attended races were held. But the biggest races of all were overseas: 45,126 people finished a half marathon in Sweden last year, and 40,763 ran one in Great Britain. 
 
 Running USA, the group that compiled the statistics for half marathon runners, points out a few other fun facts about just how many people are running these races: 
 
 Since 2010, 13.1 miles has been the second most popular distance by finishers behind the 5K. Per our count, October hosted the most U.S. half-marathons (288), while January had the least (83) in 2013. Since 2000, the number of half-marathon finishers in this country has quadrupled (482,000 to 1,960,000) or an impressive increase of 307%. 
 
 The difference between a half-marathon and 5K is huge: runners, it seems, are divided between people committed to running for maybe 40 minutes and people ready to hoof it for more than two hours. If you fall somewhere in between, well, maybe it’s about time you try for 13.1 miles. Everyone else is. ||||| In 2013, the half marathon was once again the fastest growing standard distance among U.S. road races, according to data compiled by Running USA, an industry trade group. 
 
 There were an estimated 1.96 million finishers at U.S. halfs last year, up 6% from 2012's total, and a new record. The charts and table below, created using Running USA's data, highlight some key stats and trends about the half marathon's popularity. 
 
 First, the number of finishers in U.S. half marathons has exploded. In 1990, there were an estimated 303,000 finishers. That total had more than doubled by 2004. This year's record total of 1.96 million means that, in just less than a quarter-century, there's been more than a six-fold increase in finishers. 
 
 
 
 Much of the growth has been driven by increased female participation. In 2013, women made up a record 61% of U.S. half marathon finishers, compared to 53% in 2006. Although the percentage of men finishing half marathons has fallen each of the last several years, the absolute number continues to increase. There were more than 760,000 male finishers of U.S. halfs in 2013, which was more than all finishers in 2006. 
 
 
 
 The half marathon isn't just a U.S. phenomenon. Although 14 of the 20 largest half marathons in the world in 2013 were U.S. races, the three biggest were overseas. The 45,126 finishers in Goteborg, Sweden was the most in history for an annual half marathon. 
 
 Race Number of Finishers in 2013 Goteborg (Sweden) 45,126 Great North Run (Great Britain) 40,763 Paris (France) 30,371 500 Festival (Indianapolis) 30,059 Nike Women's San Francisco 26,406 Walt Disney World (Florida) 23,148 Disney's Princess (Florida) 22,739 Berlin (Germany) 22,232 NYRR Brooklyn 21,427 Rock 'n' Roll Las Vegas 20,665 Rock 'n' Roll USA Nation's Capital 19,994 Rock 'n' Roll Philadelphia 18,137 Rock 'n' Roll San Diego 18,077 Country Music (Nashville) 18,022 Madrid (Spain) 15,943 Disneyland (California) 15,871 Miami 14,939 Surf City USA (California) 14,792 Great Birmingham (Great Britain) 14,624 NYC (New York) 14,535
– Female runners are making half-marathons the sport's most popular distance race, reports Runner's World. It takes note of new stats from Running USA showing that a record 1.95 million people finished a 13.1-mile race last year, which marks a 6% increase from the previous year and an astonishing six-fold rise since 1990. Of last year's finishers, 61% were women, up from 53% in 2004. "Runners, it seems, are divided between people committed to running for maybe 40 minutes and people ready to hoof it for more than two hours," observes Rose Eveleth at Smithsonian. "If you fall somewhere in between, well, maybe it’s about time you try for 13.1 miles. Everyone else is."