According to a study by the Center for the School of the Future at Utah State University, 30 states sold off all of the land granted as a means of guaranteeing the education of children as the country spread west. Of the 20 states that still hold lands granted at statehood, six - including Colorado - are spending revenues generated by the land rather than pouring the money into an interest-bearing permanent fund.

"With Colorado, what has raised more concerns than anything else is the lack of growth in its permanent fund that happened to coincide with banner years in which revenues from trust land was higher than any other time in history," said Richard West, executive director and professor at the Center for the School of the Future.

Colorado has retained more than 78 percent of its state trust lands, which is overseen by the State Land Board. The current inventory is about 2.8 million acres of land and 4 million acres of mineral rights. These holdings generated $146 million in 2011-12, up from $67.8 million in 2009-10. Last year, about 98 percent of the money went to public K-12 schools; most of the rest went to Fort Lewis College, the University of Colorado, Colorado State University, Colorado Parks and Wildlife, and the Colorado Department of Corrections.

Most of the revenue boom comes from oil and gas revenues, which started to soar in 2009 when new oil and gas exploration technology allowed companies to tap shale- oil formations - particularly in the Niobrara fields north of Denver.

Read more of Colleen O'Connor's story in the Denver Post.