Table:
text: Senior Advisor to the President of the United States
List of senior advisors to the president
List of senior advisors to the president
Name_ State_of_residence Took_office Left_office President_served_under_
Karl Rove Texas January 21, 2001 August 31, 2007 George W. Bush
Barry Steven Jackson Ohio September 1, 2007 January 19, 2009 George W. Bush
Pete Rouse South Dakota January 20, 2009 October 1, 2010 Barack Obama
David Axelrod Illinois January 20, 2009 January 10, 2011 Barack Obama
David Plouffe Delaware January 10, 2011 January 25, 2013 Barack Obama
Valerie Jarrett Illinois January 20, 2009 present Barack Obama
Daniel Pfeiffer Delaware January 25, 2013 present Barack Obama

Question: What is the total number of senior advisers to the President of the United States?