Organizers are expecting the largest field in 15 years for Sunday’s Honolulu Marathon.

Nearly 30,000 participants have already registered for the race, and that figure is expected to top 31,000 with late registration.

The race is on track to host the biggest field since 1997, when there were more than 33,000 competitors. Last year, more than 22,000 racers took part.

Honolulu Marathon Association President Jim Barahal attributes the increase to a number of factors, including this being the 40th running of the race. Organizers also offered a $1-a-mile entry fee for Hawaii residents early this year that drew more than 10,000 people.

Barahal also cites the strength of the yen and increased promotion. The race traditionally draws a large contingent of runners from Japan.