Each member of the Board of Commissioners shall be entitled to cast one vote for every 5,000 population, or portion thereof, in the municipality which he or she represents. Except as otherwise provided in this chapter, a majority of the votes cast shall be required to approve any action. A member of the Board may not split the votes allocated to his or her municipality. The determination of population shall be based on the latest population estimates available from the Department of Health, or other source agreed on by the Board of Commissioners.