1972

7.4

1981

6.5

1974

6.5

1952

6.7

1985

6.2

1972

6.2

1991

4.7

1990

6.1

2001

7.5

2002

6.3

1992

6.0

1966

6.6

2010

6.5

2004

6.7

1961

7.2

1948

7.9

2007

7.3

1962

7.5

2006

5.8

2010

5.7