Mobile accounts for over 50% of all referrals from Facebook

"Facebook’s emphasis on becoming a mobile company is paying off in terms of referrals, as Shareaholic reported that referrals to its network of more than 200,000 sites from Facebook mobile skyrocketed 197 percent in January compared with last September.
Shareaholic also found that Facebook mobile drove 8.25 percent of visits to its network of sites in January, while Facebook overall was responsible for 16.21 percent, meaning that mobile accounted for more than one-half of referrals from the social network.
The content discovery and sharing company offered more details in a post on its blog:
Indeed, Facebook is very much the “mobile company” everyone suggests it is.
This is demonstrated not only by the fact that mobile made up 53 percent of its advertising revenue in the fourth quarter, but by its commitment to providing a better mobile browsing experience with the introduction of its Paper application.
Effectively, if your business or blog isn’t very usable on a mobile phone, you’ll want to invest more resources into building a mobile experience your visitors can’t get enough of — or at least one they won’t hate."

Source:  All Facebook, 14th February 2014