SAN ANSELMO, CA - MAY 09: The Facebook website is displayed on a laptop computer on May 9, 2011 in San Anselmo, California. (Justin Sullivan/GETTY IMAGES)

Americans spent 121 billion minutes on social media sites in July 2012 — a staggering figure that works out to about 230,060 years spent posting, liking and tweeting.

That’s the latest number from the Social Media Report, an annual snapshot by Nielsen and NM Incite. The report says that Facebook is still the top social network, though its tally of unique visitors has fallen 4 percent from the same time last year. Blogger, the second-place network, also saw a slight decline (3 percent) while third-place Twitter saw a gain of 13 percent. Wordpress, likewise, saw a 10 percent jump.

The break-out social media star of the past year has been Pinterest, the report said, which jumped 1,047 percent from the same time last year. And since its Sept. 2011 debut, Google+ has grown 80 percent.

The report also added further evidence that the mobile Web is becoming a much more important consideration for social networks. Mobile and app traffic was significantly up for all social networks — Facebook saw app visitors grow 88 percent, while mobile Web visitors were up 85 percent. Twitter saw visitors grow 134 percent and 140 percent, respectively. No social network saw mobile traffic fall.

Overall, mobile Web use climbed 82 percent, mobile app use was up 85 percent and PC use fell 4 percent.

Social networking is a very pervasive part of modern American life. For example, 51 percent of people ages 25-34 said that they use social networking in the office, while nearly a third of the 18- to 24-year-olds surveyed say they use those sites in the bathroom.

The survey found that people spend more time on social networks than on any other category of sites — nearly a fifth of their time on PCs and 30 percent of their time over mobile devices.