1996

6.6

2002

7.0

2005

6.3

1999

6.5

2006

5.9

2001

7.3

1984

6.0

1997

6.8

2005

6.6

2005

6.9

1991

0.0

1976

3.9

2004

6.3

2000

6.3

1983

7.2

1996

7.0

1972

6.9

2005

5.5

1958

5.3

1973

7.1