PageLever, an analytics tool for Facebook pages, points to Twitter’s June 29 decision to stop syncing updates with LinkedIn as an explanation for the spike.

“The spike happened because without Twitter, there is now a significantly lower volume of content in the LinkedIn News Feed, and therefore less competition for clicks and attention,” Brendan Irvine-Broque, PageLever’s director of growth, tells Mashable in an email. “So any non-Twitter content (including links to Facebook Pages and Page Posts) is performing much better than before.”

Irvine-Broque adds that the spike happened “immediately after the change.”

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The Facebook analytics company looked at 500 Facebook pages each with more than 100,000 fans and found that the average of 7.56 percent of traffic to pages came from external referrals between March 2011 and February 2012.

MORE: Less than 10 percent of traffic to Facebook pages comes from outside Facebook.com.