2005

6.6

1980

5.6

1980

6.6

1996

5.3

2000

6.6

2006

4.7

1981

6.7

1988

7.1

1973

7.7

2003

5.7

1996

5.5

1992

6.3

2003

5.7

1995

5.9

2006

6.3

2003

6.3

2001

6.3

2002

6.0

2005

6.9

2000

5.9