1963

7.1

1967

6.6

1947

7.6

1977

6.8

1987

6.5

1987

6.5

1986

7.6

1995

8.4

1951

7.7

2001

7.8

2006

6.1

2006

6.0

2001

6.1

2005

5.4

1995

6.5

1990

6.7

2002

7.1

1992

6.9

1958

8.2

1961

7.5