1997

7.5

2006

7.2

2002

7.0

1963

7.1

2005

7.2

1990

7.7

2007

6.1

1934

7.0

2002

5.0

2003

6.3

1990

6.4

2001

6.1

2007

4.5

2002

6.5

2008

6.6

2007

6.3

2006

5.9

1978

6.3

2003

3.6

2007

6.7