Links to sources referenced:
http://www.wolframalpha.com/input/?i=chelsea+ma+vs+massachusetts+demographics
https://www.census.gov/quickfacts/table/RHI705210/25,2513205,00
http://www.massbenchmarks.org/statedata/data/mdc2015/UMDI%20Summary%20US%20Census%202015%20MA%20MCD%20Population%20Estimates.pdf