1977

7.3

1984

2.5

1972

8.7

1996

7.9

1979

8.2

2004

7.2

1993

8.6

1957

8.5

2001

7.5

1994

8.5

2000

8.2

1989

7.8

1991

8.1

1999

8.2

2006

8.2

2009

8.2

2001

7.8

1996

7.0

1980

8.4

2002

6.0