1990

6.2

2003

4.0

1939

6.9

1992

6.2

1982

6.7

1975

6.3

1944

8.1

2001

7.8

1994

7.0

1966

7.3

1983

5.9

1999

7.0

2006

6.0

2006

5.3

2008

6.6

1991

6.2

1993

6.3

2002

5.7

2003

6.3

1997

6.8