1959

7.3

1972

6.2

2004

7.2

1989

7.1

1989

6.3

1993

6.2

1995

8.0

1980

7.7

1997

7.0

1990

8.5

2004

7.4

1982

6.7

2002

7.2

1962

7.5

1967

7.7

1994

8.7

1999

7.5

1946

6.1

1980

6.5

1990

5.9