PORTLAND — Amtrak’s Downeaster set another ridership record, completing its fiscal year with 528,292 passengers, the highest in its 10-year history, officials said Tuesday.

Ridership figures for the fiscal year that ended June 30 represent the seventh consecutive year of growth, the Northern New England Passenger Rail Authority said. Ridership grew 4 percent in the fiscal 2012, and ticket revenue grew by 4.5 percent, the authority said.

The trend tracks with growing ridership overall for Amtrak, which has set records in eight of the last nine years and topped 30 million passengers for the first time last year.

The Northern New England Passenger Rail Authority, which operates the Downeaster, says it cannot pinpoint any single factor for the ridership increase. But it says surveys indicate there are more repeat customers.

“The economy comes and goes. Gas prices come and go. But we continue to gain a little bit every year,” Patricia Quinn, the authority’s executive director, said Tuesday. “It shows that more people are getting used to the service and more people are riding it more often.”

The Downeaster makes five daily trips between Portland and Boston.

Later this year, two of those daily round-trips will extend northward to Freeport and Brunswick. That will mean even more passengers with projections for an additional 36,000 riders each year, as well as another 50,000 passengers down the road when the service further expands, Quinn said.