In the county, the population was spread out with 28.70% under the age of 18, 7.60% from 18 to 24, 33.20% from 25 to 44, 22.70% from 45 to 64, and 7.80% who were 65 years of age or older.  The median age was 35 years. For every 100 females, there were 95.50 males.  For every 100 females age 18 and over, there were 92.20 males.. Which age group had the least people?