The People's Republic of China is a united multi-ethnic country. So far, 56 ethnic groups have been identified and recognized by the central government. The population of various ethnic groups differs greatly. While the Han ethnic group has the largest population, that of the other 55 ethnic groups is relatively small, so they are customarily referred to as "ethnic minorities." According to the fifth national census, conducted in 2000, the population of all the 55 ethnic minority groups totaled 104.49 million, accounting for 8.41 percent of the total population of China. People of all ethnic groups in China have made important contributions to the creation of a unified multi-ethnic country and the creation of the time-honored Chinese civilization, as well as Chinese historical progress.