Answer based on context:

In the county, the age distribution of the population shows 27.90% under the age of 18, 6.80% from 18 to 24, 31.60% from 25 to 44, 23.70% from 45 to 64, and 10.10% who were 65 years of age or older. The median age was 36 years. For every 100 females there were 96.00 males. For every 100 females age 18 and over, there were 92.50 males.

Which age group had the third most people?
45 to 64