1976

3.6

1959

4.2

2000

6.3

2003

6.0

1969

6.6

1975

5.8

2006

6.4

2006

4.7

2004

4.1

2009

5.7

2008

4.8

2003

6.8

2007

4.6

1950

5.2

2008

7.0

1933

6.2

1954

6.0

1989

4.5

1944

6.9

1964

6.3