December's Honolulu Marathon pumped an estimated $100.1 million into the state's economy and generated $5.1 million in tax revenue, according to a report released yesterday.

The amount spent by Honolulu Marathon participants and their friends and family was down slightly from $100.7 million in 2008, according to the study prepared by Hawai'i Pacific University professor Jerry Agrusa.

However, the amount of tax revenue that flowed into the state's coffers was up 21 percent from $4.2 million in 2008, the report said.

The marathon received 23,469 entries last year compared with 23,232 in 2008.

Once again, Japanese runners accounted for more than half the field (14,402). Hawai'i residents (7,036) accounted for the next largest group, followed by runners from the Mainland (1,327) and foreign countries other than Japan (704).

Agrusa's study takes into account friends and family members who accompany runners but do not run in the race.

Japanese runners were the biggest spenders, forking over an average of $315.60 a day, up 5.5 percent from last year. Agrusa said the increase in spending probably was due to the strengthening yen, which hit a 15-year high against the dollar in December.

The average Japanese participant was joined by 0.96 friends or family, unchanged from 2008, while their average length of stay fell slightly to 5.31 days.

Runners from the Mainland brought along an average of 0.99 companions, down from 1.3 in 2008. They stayed an average of 8.2 days, down from 9.3 days a year earlier.