For the fourth straight year, “facebook” was the most common search term in the U.S. this year — part of an increase in navigational searching that saw one-word searches rise 16 percent in 2012.

That’s according to Experian Marketing Services, which announced its list of 2012’s top search terms today. The data covers search activity on more than 60 search engines and website visits between January and November of this year, but doesn’t include mobile searches or traffic.

Experian says “facebook” accounted for 4.13 percent of all searches, a 33 percent increase over 2011. Other Facebook-related searches in the top 10 this year were “facebook login” (fourth), “facebook.com” (fifth) and “www.facebook.com” (eighth). Combined, those four terms made up 5.62 percent of all U.S. searches, a 27 percent increase from 2011.

Overall, the top 10 terms in 2012 were almost exactly the same as a year ago, with only “amazon” replacing “yahoo.com” as the 10th-most common term.

One-Word Searches Up 16 Percent

Seven of this year’s top ten search terms are a single word, a trend that Experian’s Bill Tancer says gained momentum in 2012.

Navigational searches continue to dominate the top search results as users continue to visit their favorite sites via search engines instead of directly entering a web address into their browsers URL bar. Single-word searches grew 16 percent in 2012 as a result of continued reliance on search engine’s suggested results.

You have to wonder if that 16 percent figure would be higher if mobile search activity was included. In that environment, users probably don’t have the patience to type lengthy queries on their smaller keypads and touchscreens.

Most-Visited Websites In 2012

Following its spot as the top search term, Facebook was also the most-visited website in the U.S. for the third year in a row. The top ten was nearly unchanged from 2011, with the exception of eBay returning to the top ten for the first time since 2009. It replaced mail.live.com (AKA Hotmail/Outlook).