2006

5.8

1997

7.5

2005

6.8

2000

7.2

1999

6.2

2000

6.5

1977

7.1

2006

7.1

2003

6.6

1998

6.5

1977

6.3

1934

6.2

2004

6.9

2005

6.7

1972

6.9

1973

7.8

1992

7.1

2005

5.2

2006

6.2

1946

7.5