2001

7.0

1967

6.6

1986

8.0

2005

6.5

1996

6.4

1981

7.9

1998

6.8

1987

7.5

1990

5.6

1997

7.6

1972

6.4

1956

7.3

1955

6.0

1977

7.3

1982

8.1

1979

8.1

1992

6.3

2007

5.7

1995

7.4

1990

7.8