the St Francis' Canossian College, the mother institute of the Chief Executive Carrie Lam, to urge "", a demand that had originated during the 13 consecutive weeks of mass protests. The imposition of the Hong Kong National Security Law (NSL) on 1 July 2020 resulted in a decline in enrollment in traditionally prestigious Hong Kong schools, as many families with the financial means chose instead to send their children abroad. A survey covering 100 schools indicated that from July to November of that year, these schools lost about 1,474 students with about 50% leaving Hong Kong with other members of their families. By 2020, mention of the Tiananmen massacre of 1989 was omitted from most new Hong Kong textbooks. By 2022, the government had introduced further authoritarian measures, ordering that foreign teachers working in Hong Kong must take an oath of allegiance. New middle school textbooks denied that Hong Kong was ever a colony, conforming to President Xi's position on the matter. The new textbooks also stated that the recent Hong Kong protests had been caused by foreign parties. Liberal studies classes were refocused on patriotism and national security, including a new National Security Education Day on April 15. In January 2023, figures were released for 2021-2022 which showed a record number of students who left Hong Kong universities before finishing their degrees, and a more than 20 year high of lecturers who left their posts. In February 2023, reports showed that around 3,500 teachers in subsidized schools left in the last academic year, with most resigning rather than retiring. Pre-school education Pre-school education in Hong Kong is not free, in principle, and fees are payable by pupils' parents. However, parents whose children have the right of abode in Hong Kong can pay for part of their fees with a voucher from the government under the Pre-primary Education Voucher Scheme (PEVS). In 2013, the amount of subsidy under the PEVS is $16,800. Primary and secondary education Every child in Hong Kong, without any reasonable excuse, is required by law to attend a primary school after the child has attained the age of 6. They are also required to attend a secondary school after primary education and is completed before he/she attains the age of 18. However, a student who has completed Form 3 of secondary education and whose parent can produce evidence to the satisfaction of the Permanent Secretary for