Nationwide, undergraduate enrollment is down in spring 2018. But, it's not so in Arizona, where the undergraduate population is steadily growing and now ranks third nationwide for states with the largest increase in enrollment.

Jason Dewitt is a research manager at the National Student Clearinghouse Research Center. He said changing population demographics now drive college enrollment as the next generation to enter college is a smaller one.

He said post-Baby Boom, in the late 70s and 80s, there was an enrollment crisis over Gen X students, also a smaller generation than its predecessor. But gender equality solved the problem then.

“The crisis never materialized because women began enrolling in college in much higher numbers,” Dewitt said.

Women now outnumber men on college campuses. Dewitt said the question at hand is what group is out there who will enroll in the future.

"First-generation students are going to be accounting for an increasing number of the high school graduates, Hispanic students in particular," Dewitt said.

The National Student Clearinghouse Research Center compiles enrollment numbers in May and December, during graduation and enrollment. Compared to spring last year, the number of students age 18-24 declined by 275,000.

And enrollment in that age group has fallen by more than 1.5 million since spring 2011, when the economy began to recover from the recession. The report says the nationwide enrollment decline is largely due to non-traditional students exiting programs.