1997

4.9

1989

6.7

1996

6.7

2000

6.3

1994

6.0

2004

6.1

1995

6.2

1999

6.5

1995

7.2

1999

8.1

2001

7.8

1996

7.1

2001

5.4

2001

6.6

2005

4.5