1934

4.1

1990

7.7

1966

7.1

1999

7.1

2006

5.8

2008

6.6

2001

7.3

2002

6.2

1997

6.8

1960

7.2

1975

6.9

2006

5.4

1950

6.8

1956

6.5

2005

7.5

2007

6.5

2007

7.6

2007

7.2

2001

6.3

2004

7.0