1997

8.1

2005

8.0

2005

6.2

2005

4.9

2008

5.2

2000

8.2

2004

4.7

2000

8.5

1990

5.5

2002

7.9

1995

6.6

1996

5.4

1999

6.0

2008

4.4

2003

6.0

2005

7.5