1984

7.3

1998

7.2

1992

7.5

1995

6.5

1998

7.4

1960

7.6

2002

6.9

1999

6.2

2005

7.2

1987

7.0

2007

6.8

1988

5.2

1979

6.9

1996

4.0

1982

7.6

1974

8.0

1996

7.5

1984

7.3

2002

6.3

1990

7.7