DOVER — Rep. Debra Heffernan, D-Edgemoor, announced Thursday she intends to file legislation that would raise the minimum schooling age from 16 to 18.

Currently, Delaware students age 16 or older are not required to enroll in school. The draft bill, which is similar to unsuccessful legislation filed by Rep. Heffernan in 2012, would phase in the change over two years, first bumping the age limit to 17 in 2016. It would include an exemption for students who have the permission of both a parent and a health professional, as well as those who graduate before age 18.

“We stress over and over how invaluable an education is to being successful in life,” Rep. Heffernan said in a statement. “We see more and more of that in the 21st century. A high school diploma is no longer optional.

“It really is the minimum education for young people today who want economic success and independence. As we continue working to improve our educational system, we need to have students staying to complete their coursework.”

The 2012 bill had 16 sponsors but was tabled in committee.

According to the National Center for Education Statistics, 23 states require school attendance for students under 18, and 11 require it until students reach age 17. The U.S. Census Bureau reported high school graduates with no other education made about $10,000 more than dropouts in 2009.

“On one hand, schools are trying hard to increase the graduation rate,” Rep. Heffernan said. “On the other, we are saying it is OK to drop out of school at 16. We need a consistent message and consistent policies.”

The proposal will also be sponsored by Rep. Stephanie Bolden, D-Wilmington, and Sen. David Sokola, D-Newark.