1992

6.8

2003

7.2

2007

3.1

1999

7.3

1994

6.4

2000

7.2

1988

6.6

2005

5.9

1976

6.0

2003

6.7

2012

7.8

1943

6.0

1937

6.0

1968

6.2

1995

5.7

1923

7.5

1960

7.5

2008

5.2

1999

6.7

1984

6.5