South Carolina maintained its No. 3 ranking nationally for its total number of National Board Certified teachers, according to figures released Tuesday by the National Board for Professional Teaching Standards.

The state had 291 educators earn the teaching professionís highly respected credential in 2012, increasing the stateís number of nationally certified teachers to 8,436. South Carolina lags only North Carolina and Florida.

In the Lowcountry, both Dorchester 2 and Charleston had 18 additional educators earn the certification last year while Berkeley had 10. Rural Dorchester 4 had 2.

Charleston has the most board certified teachers locally with 488, and it ranks third statewide behind Richland 2 and Greenville.

To become certified, teachers must complete a two-part process that can last up to three years. They must prepare a portfolio with videotapes of classroom teaching, lesson plans, student work samples and reflective essays, and they must complete assessment center exercises based on content knowledge that prove they have mastered the subjects they teach.

South Carolina gives new teachers earning the certification a $5,000 salary supplement annually for 10 years.