Florida's population has grown principally from in-migration and immigration. NaturalÊincrease, however, does account for approximately 12 percent of Florida's growth.  BirthÊrates are highest among blacks and second highest among Hispanics, although birth rates vary considerably within the Hispanic population.  Birth rates are higher than the state Hispanic average among Mexican and Puerto Rican women, but lower among Cuban women.  The average young Cuban family is approximately the same size as the average young non-Hispanic white family.  The highest fertility rates in the state occur in rural counties.