The 2000 census data is available from the U. S. Census Bureau . While the data from this census is still being analyzed there is comparative data from the 1990 and 2000 census on the total number of Indian people in the United States. You can also view map of the percentage change of Native population by state, a table of counties ranked by numeric change in American Indian and Alaska Native population from 1990 to 1999, states ranked by Native American population based on the 2000 census data, a table of counties ranked by percent change in American Indian and Alaska Native population from 1990 to 1999, and a population profile of American Indians . This site will allow you to research the Native populations in each of the 50 states. You can look up the statistics for the 25 most populous Tribes in the United States (Lakota and Dakota are listed as Sioux) based on the 1990 data. You can also see the 1990 data on American Indian Languages spoken at home. You can look up the 2000 census data by state and county. States with high Dakota and Lakota populations include North Dakota, South Dakota, Montana, and Nebraska. Note that some of this information is based on the 1990 census data. The census bureau also provides a useful summary of its data for American Indian Heritage Month: 2000.
Ethnologue: Languages of the World, a book and CD ROM resource, provides stastical information on Dakota speakers in the United States, as well as Dakota speakers in Canada. Census information is also available for Lakota speakers in the United States and Canada. Lakota and Dakota are members of the Siouan language family.