The Portland Museum of Art has finished 2012 with the second-highest attendance in museum history and the highest visitor count in more than a decade. The museum had nearly 178,000 visitors for the year, a 34 percent jump over 2011. The museum set a one-month attendance record in December, when nearly 26,000 people visited, drawn by a Winslow Homer exhibition. Director Mark Bessire said the museum had a successful year in terms of attendance, membership, store and cafe sales, and fundraising. He said the museum’s national reputation was boosted with the opening of its Winslow Homer art studio in Scarborough and its successful Homer exhibition.