The population of Rio de Janeiro on December 21st 2011 is approximately 6,391,201. (Extrapolated from a population of 6,186,710 in 2008 and a population of 6,323,037 on December 2nd 2010.)
The population of Rio de Janeiro on January 1st 1991 was approximately 5,090,414. (Extrapolated from a population of 6,186,710 in 2008 and a population of 6,323,037 on December 2nd 2010.)
Depending on what website you look at, the number ranges from about 600 to 750. According to the 2000 census in Brazil this number sits at 513 in Rio with 612 in Sao Paolo and a total sitting at 881...