1965

6.8

1984

6.4

1991

7.3

2001

6.2

1987

6.7

1962

5.7

1994

6.1

2007

6.0

1972

4.5

1972

6.5

1984

5.9

2001

6.6

2005

6.2

1975

6.9

2001

7.2

2003

8.3

1946

5.6

1975

6.9

1990

6.1

1990

4.6