Simplify the following text for a Grade 7 native English-speaking person.
Original: He had a peak Elo rating of 2780 , and his 90 total months at world number-one are second all-time behind only Garry Kasparov since the inception of the FIDE ranking list in 1971 .
Simplified: He had a peak Elo rating of 2780 , and his 90 months at world number one are second only to the record of Garry Kasparov .