1997

7.5

1998

6.5

2006

6.6

1994

8.7

1982

7.6

1996

7.0

1993

6.2

1969

6.2

2007

6.5

1958

6.6

1990

6.9

1973

3.7

1970

7.1

1970

7.5

1983

6.7

2002

7.7

1988

6.9

1979

7.3

2004

6.6

1958

7.1