The share of adult internet users who have a profile on an online social network site has quadrupled in the past four years, from 8% in 2005 to 35% now, according to the Pew Internet & American Life Project's December 2008 tracking survey. Younger online adults are much more likely than their older counterparts to use social networks, with 75% of adults 18-24 using these networks, compared to just 7% of adults 65 and older. Overall, personal use of social networks seems to be more prevalent than professional use of networks, both in the orientation of the networks that adults choose to use as well as the reasons they give for using the applications. Most adults, like teens, are using online social networks to connect with people they already know. When users do use social networks for professional and personal reasons, they will often maintain multiple profiles, generally on different sites. Most adult social network users are privacy conscious; 60% of adult social network users restrict access to their profiles so that only their friends can see it, and 58% of adult social network users restrict access to certain content within their profile.