Tourism travel is up this summer over last year in Maine, the state Tourism Office is reporting.

An estimated 13.7 million day travelers and an additional estimated 9.5 million overnight travelers visited the state this summer, according to traveler data collected by Davidson-Peterson Associates, a travel and tourism research firm in Kennebunk that represents the office.

The total marks an increase in day visits of 8 percent over the summer of 2009, with overnight visits up 14 percent over a year ago.

The data also shows that many travelers came for outdoor recreation or take advantage of shopping opportunities.

The report also indicates that the vast majority of both day and overnight travelers plan to return to Maine for a future trip, and are likely to recommend Maine as a travel destination to friends or relatives.

Tourism generates approximately $8 billion in sales of goods and services and contributes more than $400 million in state and local tax revenue.