Each state of the United States selects two senators to represent their states in the United States Senate. In 1913, the 17th Amendment[?] to the United States Constitution provided for the direct popular election of senators; prior to this, senators were selected by state legislatures.
... spread out with 20.5% under the age of 18, 6.1% from 18 to 24, 24.6% from 25 to 44, 28.2% from 45 to 64, and 20.7% who are 65 years of age or older. The median age is 44 ...