Engines Idling Roughly
"It appears, however, that people are comfortable clicking around on their own. Only 7 percent of Web pages are accessed through a search engine, a portion that has remained almost static since 1999."

Hello? Once you know a site, do you need a search engine to get back to it, unless you lost of forgot its url? What's important is how people discover sites more than how they access them on a daily basis.