1987

6.5

1990

6.0

1999

6.7

2003

7.2

2004

7.2

2004

5.8

2005

6.2

1996

6.0

2002

6.7

1986

6.2

1996

5.9

1994

6.2

2000

3.8

2004

6.4

1990

6.8

1980

6.2

2005

6.6

1999

6.2

2004

5.2

1999

6.5