Carleton (10/26/2009)
I agree, excellent article Gail. I'll also be looking for the follow-up articles. -Carleton
I believe this is somewhat dependent on the index and pages therein, but it has been shown here on sqlservercentral.com that the percentage is VERY low, typically on the order of 1% or so of the total rows.
Best,
Kevin G. Boles
SQL Server Consultant
SQL MVP 2007-2012
TheSQLGuru on googles mail service