This does not negate, however, the scope and breadth of traditional and home education provided by Navajo families and custom since before the US annexation. Education, and retention of the Navajo student, are significant priorities. Major problems faced by the Nations surrounds building competitive GPAs for students on a national level, coupled with a very high drop-out rate among high school students. Over 150 public, private and Bureau of Indian Affairs schools serve Nation students from kindergarten through high school. Most schools are funded from the Navajo Nation under the Johnson O’Malley program. The Nation runs community Head Start Programs, the only educational program fully operated by the Navajo Nation government. Post-secondary education and vocational training are available on and off the territory. The Navajo Nation operates Tséhootsooí Diné Bi'ólta', a Navajo language immersion school for grades K-8 in Fort Defiance, Arizona. Located on the Arizona-New Mexico border in the southeastern quarter of the Navajo Nation, the school strives to revitalize Navajo among children of the Window Rock Unified School District. Tséhootsooí Diné Bi'ólta' has thirteen Navajo language teachers who instruct only in the Navajo language, and no English, while five English language teachers instruct in the English language. Kindergarten and first grade are taught completely in the Navajo language, while English is incorporated into the program during third grade, when it is used for about 10% of instruction. The Nation has six systems of secondary academic institutions that serve Navajo students, including:  The Navajo Nation operates Diné College, a two-year community college with its main campus at Tsaile in Apache County, Arizona. The college also operates seven other sub-campuses throughout the nation. The Navajo Nation Council founded the college in 1968 as the first tribal college in the United States. Since then, tribal colleges had been established on numerous reservations and now total 32. Diné College has 1,830 students enrolled, of which 210 are degree-seeking transfer students for four-year institutions. The college includes the Center for Diné Studies. Its goal is to apply Navajo "Sa'ah Naagháí Bik'eh Hózhóón" principles to advance quality student learning through "Nitsáhákees" (thinking), "Nahat'á" (planning), "Iiná" (living), and "Siihasin" (assurance) in study of the Diné language, history, and culture. Students are prepared for further studies and employment in a multi-cultural and technological world.