„Results from a German survey of 4,000 parents in 2014/15 showed some 5 % of primary and 18 % of secondary school students received tutoring. In England and Wales (United Kingdom), 27 % of 11- to 16-year-old students, and as many as 41 % in London, had received private tutoring at least once in their academic careers. […] In China, one third of primary and one half of upper secondary school students receive supplementary tuition; among the latter, students in urban areas are twice as likely to receive tuition as their peers in rural areas.“
UNESCO (Hrsg.), Non-state actors in education (2021), S. 51.