1999

6.2

1990

6.3

1993

7.9

2008

6.1

2008

6.5

1973

7.5

1991

6.9

2002

5.3

1945

8.1

1999

7.3

2000

7.4

2005

6.7

1995

7.9

1987

8.0

1999

5.8

1999

7.1

1981

7.2

2002

6.4

2003

6.0

2000

4.4