Simplify the following text for a Grade 7 native English-speaking person.
Original: He was ranked # 1 in the world from April 2006 to January 2007 , during which his Elo rating was 2813 , which had been surpassed only by Garry Kasparov , and subsequently by Magnus Carlsen and Anand .
Simplified: He was ranked # 1 in the world from April 2006 to January 2007 , and had the second highest Elo rating of all time ( 2813 ) .