Simplify the following text for a Grade 5 native English-speaking person.
Original: In his first season , he appeared in all 44 of the Bruins ' games , posting 12 shutouts and a 1.15 goals-against average , the second lowest goals-against average in NHL history through the 2008 season , after George Hainsworth 's 0.98 the same season .
Simplified: In one full season , a goals-against average of 1.15 is the second-lowest ever in NHL history . George Hainsworth has a lower goals-against average of 0.98 that season , which is the lowest-ever goals-against average for a full season .