1986

6.2

1997

6.8

7.9

1994

8.5

1955

6.3

1958

7.8

1985

8.3

2014

6.9

1952

7.3

1975

8.4

1983

7.4

1956

8.0

1990

8.5

1971

7.2

2000

7.3

1989

7.8

2000

8.2

1999

7.3

2005

7.2

1987

8.1