1976

8.0

1961

7.7

1965

7.0

1985

7.2

2009

6.5

5.7

2004

7.5

1973

6.1

2006

6.4

1993

7.3

1991

7.0

1936

7.4

2002

6.1

1942

6.9

1969

6.2

1983

7.3

2008

0.0

1990

5.6

2014

5.8