AUGUSTA – More Maine high school graduates want to go to college, but fewer attain that dream, according to a study released this week by the Sen. George J. Mitchell Scholarship Research Institute.

The number of Mainers who left high school with plans to attend college increased from 2001 to 2005, but enrollment actually dropped, the study found. The widespread practice of academic tracking was cited as the biggest factor in keeping students from going on to college.

The study was based on interviews with students at 20 high schools and surveys of more than 3,000 educators, parents, students and young adults.

It found that 64 percent of seniors graduating in 2001 said they planned to attend college, compared with 70 percent in 2005. But enrollment during the four-year period slipped from 62 percent to 57 percent.

Despite an above-average high school graduation rate, Maine has continued to lag behind the rest of the region and the nation in college degrees attained by adult residents.

Last year, 27 percent of Mainers 25 or older had bachelor’s degrees. The rate for the other five New England states was 35 percent, and the national average was 28 percent.

The decline in college enrollment comes as the state is making a major push to raise college admission levels. The Department of Education now requires all students to take college-entrance exams, and legislation enacted this year will require every high school student to fill out an application to a college or other post-secondary school, or the military.

The study found that academic tracking, in which high schools place students in courses based on academic performance, was the chief barrier to college attendance, said Lisa Plimpton, director of research for the Mitchell Institute.

“The data clearly show that students in a general/vocational track are less challenged in the classroom, receive less encouragement about college and do not feel as well-prepared for life after high school,” the report says.

The Department of Education is drafting a legislative proposal to end tracking by 2010.