Governor Mark Dayton greets a kindergartner at Garden City Elementary in Brooklyn Center, Minn., on the first day of statewide all-day kindergarten, Sept. 2, 2014. Tim Post | MPR News 2014

In the first year that Minnesota offered free all-day kindergarten statewide, 57,714 students enrolled.

Before this year, 54 percent of students had access to all-day kindergarten. In some school districts, parents had to pay as much as $4,000 a year for the option.

The enrollment exceeded the state's estimates by 3,500 students.

That shows that families want the all-day option, said Brenda Cassellius, commissioner of the Minnesota Department of Education.

"School districts knew that but they didn't have the resources to do it," she said. "This is just a wonderful piece that we really think is really going to be a game changer for us in closing the achievement gap."

Cassellius hopes all-day kindergarten will improve test scores for students of color and low-income students as they progress to later grades. She said it gives teachers more time to work with students.

"It's just a really well-rounded program throughout the day rather than trying to squeeze everything into just a few hours," she said.

State lawmakers approved $134 million to fund all-day kindergarten in 2013. This session, Gov. Mark Dayton is asking lawmakers for $347 million to fund free all-day preschool for all of the state's four-year olds.