On Tuesday Oct. 17, the US reached a milestone: Its population grew to 300 million. Today, the US population has a median age of 36.2 and a life expectancy of 77.8, according to the US Census Bureau. Well over half (59%) of women are in the workforce and 85.2% of people ages 25 and older have at least a high school diploma.

To commemorate this milestone, eMarketer reviews its estimates of the current demographic makeup of the US Internet population.

As of 2006, 63% of the US population ages 3 and older uses the Internet at least once per month, according to eMarketer. That amounts to 180 million people.

Hispanic Internet users number 16.7 million, comprising 9.3% of US Internet users, according to eMarketer. By comparison, 14% of the US population is of Hispanic origin, according to the Census Bureau.

Whites make up 74.8% of US Internet users, according to eMarketer, and 74.7% of the total US population as of 2005, according to the Census Bureau.

US Internet users ages 50 and older total 46.8 million, or 26% of the total US Internet user population. Adults ages 50 and older make up an estimated 29.4% of the US population, according to eMarketer estimates based on Census Bureau data.

Women Internet users total 92.6 million, and 87.5 million US Internet users are men. Women make up 51.4% of the US Internet user population.

Children are also on the Internet, with 40.1% of those ages 3 to 11 and 73.7% of teens ages 12 to 17 using the Internet at least once a month.