Half Web Searchers Enter One Query, Look at One Page of Results
http://www.usabilitynews.com/news/article1213.asp

Light, Ann
Usability News
2003

Abstract:

Over 66% of searchers examine fewer than five results with more than one in three Web searchers viewing only on one document in a given session. Users' search strategies are not those believed traditionally effective, but a close analysis reveals they work well on the Web.