Complex sentence: The 1881 census grouped the people into 6 main ethnic categories further subdivided into 47 sub-categories, and by 1921 the 6 broad groups were given as Europeans, Eurasians, Malays, Chinese, Indians and others.
Split into simpler sentences: The 1881 census grouped the people into 6 main categories, and further subdivided into 47 sub-categories. By 1921 the 6 broad groups were given as Europeans, Eurasians, Malays, Chinese, Indians and others.