It could be deduced that the persons over the four (4) distinct age ranges within the three (3) geographical areas exhibit diverse trends and patterns. The percentages for persons under 5 were the least for all geographic areas, with the least percentage at 4.4% being exhibited in San Francisco. The information on the percentages of the population was collected for the year 2010 (U.S. Census Bureau, 2010). The greatest segment of the population is that which is within the 18 to 65 years of age for all geographic locations, with the greatest population exhibited in San Francisco at 73%. Moreover, in the age structure of persons under 18, the state of California, in general, exhibited the greatest percentage at 25%, followed by Pleasant Hill at 19.8%. One could surmise that the differences in diverge of population of persons within the age range of 18 to 65 years old in the city of San Francisco is the employment opportunities that abound in the area, when compared to opportunities for employment in Pleasant Hill. The age range of 18 to 65 signifies the need for the segment to earn a living to be able to support themselves and their family members. Concurrently, for the age range of persons 65 and over, the chart shows that the percentages in San Francisco and in Pleasant Hill are almost the same at 13.6% and 13.9%, respectively. The reason one could think of is that people migrate to other states at the onset of retirement, or could have died. As such, the percentages of the population.