Is there a reason why UNC Chapel hill takes more in-state students

Colleges and Universities A-Z University of North Carolina - Chapel Hill
1

Looks like UNC Chapel Hill only accepts 15 % of OOS students. Is there a reason behind this?

2

http://mediahub.unc.edu/university-ratio-unc-systems-82-18-split/

3

And it is a state university that gets significant funding from the taxpayers of the state.

4

^ And the NC General Assembly – which represents the taxpaying citizens of North Carolina – presumably wants those citizens to reap the benefit of all those taxes by providing that more of their children are able to take advantage of its flagship public university.