1994

6.7

1998

6.8

1990

5.8

2003

4.9

1989

6.2

2003

6.2

1981

6.2

2006

5.3

1982

5.9

1984

6.1

1985

5.3

1962

7.0

1963

7.1

1967

6.6

1977

6.8

1987

6.5

2005

6.3

2006

7.5

2002

6.3

1959

8.0