The increase, which took place between 1995 and 2005, far outpaced the 10 percent hike in regular public school enrollment, USA Today reported Monday.

Education experts attribute the rise to more mothers in the workforce as well as states stepping up to finance preschool programs.

A new study released by the Rand Corp. says funding pre-K programs can actually save states money if it the need for social services later in life and produces increased tax revenue when pre-school students get higher-paying jobs.

"There's growing evidence that supports the idea that prevention has an advantage over treatment," Rebecca Kilburn, Rand Corp. economist, told USA Today.

However, the Rand report points out that not all pre-K programs offset their costs.

The National Institute for Early Education Research at Rutgers University puts the cost of preschool to states at $3,642 per child.