2010: The number of emails to and from non-government accounts sharply increases.

In 2010, Clinton’s first full year as secretary of state, an internal study finds that in one week, more than 9,200 emails are sent from the State Department’s Executive Secretariat servers to 16 web-based email domains, including gmail.com, hotmail.com, and att.net. These could include both work-related and personal emails. (US Department of State, 5/25/2016)