36) stated that parents are responsible for the education of their children, "by regular attendance at school or otherwise", which allows children to be educated at home. The legislation places no requirement for parents who choose not to send their children to school to follow the National Curriculum, or to give formal lessons, or to follow school hours and terms, and parents do not need to be qualified teachers. Small but increasing numbers of parents do choose to educate their children outside the conventional school systems. Officially referred to as "Elective Home Education", teaching ranges from structured homeschooling (using a school-style curriculum) to less-structured unschooling. Education Otherwise has supported parents who wished to educate their children outside school since the 1970s. The state provides no financial support to parents who choose to educate their children outside of school. Post-16 education Students at both state schools and independent schools typically take GCSE examinations, which mark the end of compulsory education in school. After this, students can attain further education (the "sixth form"); this can either be in the sixth form of a school or a specialized sixth form or further education college. Alternatively, students can also opt for apprenticeships instead of a sixth form. In the 16–17 age group by August 31, sixth form education is not compulsory, but mandatory education or training until the age of 18 was phased in under the Education and Skills Act 2008, with 16-year-olds in 2013 and for 17-year-olds in September 2015. While students may still leave school on the last Friday in June, they must remain in education of some form until their 18th birthday. Above school-leaving age, the independent and state sectors are similarly structured. Sixth form colleges / further education colleges Students over 16 typically study in the sixth form of a school (sixth form is a historical term for Years 12–13), in a separate sixth form college, or in a Further Education (FE) College. Courses at FE colleges, referred to as further education courses, can also be studied by adults over 18. Students typically study Level-3 qualifications such as A-Levels, BTEC National Awards and level-3 NVQs. Some 16–18 students will be encouraged to study Key Skills in Communication, Application of Number, and Information Technology at this time. Apprenticeships and traineeships The National Apprenticeship Service helps people 16 or more years of age enter apprenticeships in order to learn a skilled trade.