2005

4.5

2004

5.2

2003

6.2

2002

4.4

2002

4.3

2002

3.9

2001

4.0

2000

5.0

1998

7.8

1998

7.3

1997

6.2

1996

3.5

1995

6.0

1994

6.3

1993

7.7

1993

6.0

1992

7.0

1992

7.6

1992

6.5

1992

5.5