Simplify the following text for a Grade 11 native English-speaking person.
Original: After a long and difficult fight with myelodysplasia , which included three bone marrow transplants , Sagan died of pneumonia at the age of 62 at the Fred Hutchinson Cancer Research Center in Seattle , Washington , on December 20 , 1996 .
Simplified: After a long and difficult fight with myelodysplasia , Sagan died at the age of 62 , on December 20 , 1996 , at the Fred Hutchinson Cancer Research Center in Seattle , Washington .