In the United States and Canada, a school of education (or college of education; ed school) is a division within a university that is devoted to scholarship in the field of education, which is an interdisciplinary branch of the social sciences encompassing sociology, psychology, linguistics, economics, political science, public policy, history, and others, all applied to the topic of elementary, secondary, and post-secondary education. The U.S. has 1,206 schools, colleges and departments of education and they exist in 78% of all universities and colleges. According to the National Center for Education Statistics, 176,572 individuals were conferred masters' degrees in education by degree-granting institutions in the United States in 2006–2007. The number of master’s degrees conferred has grown immensely since the 1990s and accounts for one of the discipline areas that awards the highest number of master’s degrees in the United States.