1950

8.1

1962

8.0

2002

8.4

1998

6.4

2002

4.4

1973

5.1

1993

6.3

1971

7.5

1996

7.7

1993

7.9

2001

6.1

2000

6.3

1996

7.0

1996

7.4

1960

7.7

1953

7.1

2004

6.3

2007

6.7

2000

6.5

2007

6.8