1997

6.6

1989

7.4

2002

5.2

1966

6.8

2003

5.3

1977

5.2

1969

6.1

2003

7.2

1974

5.2

1986

5.7

1972

6.1

2008

4.8

1941

6.9

1982

6.2

1961

7.8

2009

6.1

1937

6.7

1951

7.2

2006

5.0

2007

6.2