A German teacher is trained and certified for specific subjects. A lesson taught by a teacher without that certification is called fachfremd, foreign to the subject. The share is counted. In 2016, the education union GEW reported figures from a national school study of 2012, for lower secondary schools other than the Gymnasium. In physics, 18 percent of the teachers taught the subject fachfremd. In mathematics the figure was 15 percent. In biology it was just under 13 percent, and in chemistry 10 percent. In mathematics the states differed widely, from 36.4 percent of teachers in Bremen to 1.9 percent in Thuringia.