In 2011-12, the percentage of public secondary schools who reported requiring that students wear uniforms (12 percent) was lower than the percentages of elementary schools (20 percent) and combined schools (30 percent) with such a requirement.esponse: Between the 2003–04 and 2011–12 school years, the percentage of public schools reporting that they required that students wear uniforms increased from 13 to 19 percent.