context: After Malaysia's independence in 1957, the government instructed all schools to surrender their properties and be assimilated into the National School system. This caused an uproar among the Chinese and a compromise was achieved in that the schools would instead become "National Type" schools. Under such a system, the government is only in charge of the school curriculum and teaching personnel while the lands still belonged to the schools. While Chinese primary schools were allowed to retain Chinese as the medium of instruction, Chinese secondary schools are required to change into English-medium schools. Over 60 schools converted to become National Type schools.
question: When was the National School system assimilated?