There are 78 municipalities in Puerto Rico.
Names from CIA World Factbook (http://www.cia.gov/cia/publications/factbook/geos/rq)
... household size is 2.41 and the average family size is 2.88. In the town the population is spread out with 20.6% under the age of 18, 5.0% from 18 to 24, 26.8% from 25 to ...