1973

6.3

2004

6.1

1981

6.9

1965

7.9

1969

5.1

1966

7.1

2007

6.2

1993

6.5

1986

6.0

1987

6.9

1991

4.7

2001

6.9

1984

7.2

1982

6.8

1984

7.2

1992

4.7

1961

7.9

1989

5.7

1971

6.5

1956

7.1