If you ever get the feeling that you spend too much of your time on either Facebook or Twitter, don't worry—you're not alone. According to a new Nielsen report, the U.S. spent 121 billion minutes on social media in the month of July. Maybe you should worry. Just a little. 

The "Social Media Comes of Age" report found that "consumers continue to spend more time on social networks than on any other category of sites—roughly 20 percent of their total time online via personal computer (PC), and 30 percent of total time online via mobile." 

It also found that Facebook is the most popular social network, by far, with 152.2 million unique visitors a month. Twitter came in third with 37 million visitors, while Tumblr hit eight with 25.6 million. Surprisingly, Pinterest came in sixth with 27.2 million visitors, a 1,047 percent increase from 2011. 

Facebook and Twitter came in first and second place, respectively, when it come to visitors who accessed the networks via apps and the mobile web. Every social network showed double-digit mobile growth, meaning the number of minutes spent on these networks will rise come next year. 

At least people won't be sitting in their crib lurking on Twitter. They'll be outside or at a party lurking on Twitter. #Progress.

[via NBC News]