This compares audience composition of the site to the entire
Internet population. The higher the index number, the more
concentrated a site is in a particular demographic. As an
example, if a site indexes 100 for age 18-24, that means a given
visitor to it is as likely to be 18-24 as any internet user
chosen at random. An index of 200 means the visitor is twice as
likely to be 18-24, 50 means half as likely, and so on. 2.
Segments are represented with icons. Segments include gender,
age, household income, and education. 3. Very High Indexes (over
200) are denoted with a plus symbol. 4. Internet Average is
represented by the dotted vertical line.