1997

6.7

1981

8.3

1989

6.2

1999

7.6

2006

7.7

1999

6.7

2006

7.1

1993

5.9

2004

6.6

2005

8.4

2004

6.9

1997

6.5

1985

7.7

2002

8.4

2007

0.0

2004

9.0

1966

7.2

2001

5.0

1964

6.1

2003

0.0