AUSTIN -- University of Texas System regents on Thursday ordered their campuses to offer students a four-year, fixed-rate tuition option by fall of 2014 to encourage them to graduate on time.After a decade of rising tuition costs, Gov. Rick Perry has been pushing universities to offer fixed-rate tuition to help students and their families budget for college. The Legislature also is considering writing the four-year tuition option into state law.The UT system has nine campuses with about 216,000 students. UT-Dallas has had fixed-rate tuition since 2008, and UT-El Paso has been offering an optional plan since 2006.Under the regents' order, the other seven schools will be required to develop optional fixed-rate plans. Each campus would set its tuition charges.For the 2011-12 and 2012-13 academic years, UT-Arlington has offered "flat-rate tuition" -- tuition plus fees -- that average $9,292, a spokeswoman said.Supporters say the fixed-rate plan will encourage students to graduate in four years. The four-year graduation rate at UT-Dallas for students entering in the fall of 2006 was 45 percent. That number jumped to 51 percent for students who entered in fall 2008, once the school adopted its four-year tuition plan.Texas college students have faced significant tuition spikes in recent years, with the average student at a state university paying 55 percent more than a decade ago.The state set tuition caps until 2003.