1967

6.5

1981

6.8

1999

6.0

1986

6.8

1994

6.2

1976

7.3

1985

6.5

1964

6.6

1988

7.0

2004

3.4

2005

6.7

2014

6.4

1979

7.8

1945

6.1

1951

7.3

1982

6.1

1978

6.1

1964

7.1

1969

6.7

2010

6.1