A pre-2010, unofficial census report contains some interesting statistics.
Dorchester's total population on August 12, 2009: 113,311.
African American or Black: 34%
African American: 20%
Other Carribean descent: 4%
African descent (not naturalized): 2%
White non-hispanic: 32%
Uncommitted Euro-American: 10%
Foreign born Europeans (not naturalized): 3%
Boston Brahmin Blue Blood: 0.5%
Hispanic or Latin: 8%
Asian or Pacific Islander: 20.5%
South Vietnamese-American: 12%
Foreign born Vietnamese (not naturalized): 4%
Cape Verdean: 4%
Some other race (including one or more claimed and Native Amercian): 1%
For a frame of reference, Wikipedia provides the following stats: "As of 2000 the population of Dorchester was 92,115 and the ethnic makeup was 36% African American or Black, 32% White non-Hispanic, 12% Hispanic or Latino, 11% Asian or Pacific Islander, 1% Native American, 4% some other race, 5% two or more races."
The article's anonymous author also notes that when Dorchester was annexed to Boston in 1870, the town was primarily rural with a population of 12,000. After annexation, the population grew to 150,000 in 1920. Though it shrank after 1950, it is on the rebound and increasing again.
These more recent, unofficial numbers and additional categorization lends credence to the accepted notion that Dorchester is a neighborhood open to anyone who cottons to moving here. It also speaks well of Dorchester that so many cultures co-exist side by side with little strife and nary a kerfuffle. Dorchester really is Boston's most welcoming neighborhood where opportunity abounds. Immigration is up along with accompanying gentrification. Dorchester remains an affordable neighborhood overall, however, and hence the net gain in population.
Be warned, the statistics cited in this article have not been verified by an independent agency, nor are they endorsed by or reported by the federal government or any other official or quasi-official municipal agency. Figures were determined by a secret formula and direct observation by the Illumadotti. Inquiries as to methodology and sample populations can be directed to that organization's secret address.