" 
 :It is considered reliable because it uses official census data. Census data is usually more preferred on Wikipedia. See Los Angeles for example. The city or the state of California, can't remember which, has a population estimate for Los Angeles, but census data is used instead. In most cases the metropolitan population is greater than the city population. This is because many cities have suburbs which have strong economic ties to the central city. But that is not always the case. See Chongqing for example.    () "