The educational system prevailing in the state's schools specifies an initial 10-year course of study, which is divided into three stages: lower primary, upper primary, and secondary school—known as "4+3+3", which signifies the number of years for each stage. After the first 10 years of schooling, students typically enroll in Higher Secondary Schooling in one of the three major streams—liberal arts, commerce, or science. Upon completing the required coursework, students can enroll in general or professional undergraduate (UG) degree-college programmes. The majority of public schools are affiliated with the SCERT Kerala. There are 15,892 schools under the SCERT, of which 5,986 are government schools, 8,183 are aided schools, and the rest are either un-aided or technical schools. Other educational boards are the Indian Certificate of Secondary Education (ICSE), the Central Board for Secondary Education (CBSE), and the National Institute of Open Schooling (NIOS). English is the language of instruction in most self-financing schools, while government and government-aided schools offer instruction in English or Malayalam. Though the cost of education is generally considered low in Kerala, according to the 61st round of the National Sample Survey (2004–2005), per capita spending on education by the rural households was reported to be for Kerala, more than twice the national average. The survey also revealed that the rural-urban difference in household expenditure on education was much less in Kerala than in the rest of India.