1972

6.9

2004

5.3

2003

6.0

1988

6.2

2008

6.5

1940

6.0

2007

7.1

1959

6.8

2005

7.1

2003

6.1

1996

7.0

2000

6.7

1993

8.1

2014

6.5

1986

6.2

1970

7.6

1965

5.6

2007

6.8

1989

5.2

1988

6.5