1987

6.5

1987

6.3

1998

5.8

2001

6.3

1987

7.3

1994

5.9

2004

6.8

2006

6.0

2006

6.9

2001

6.2

2005

6.0

1980

7.7

1994

7.4

2003

7.8

2004

7.3

1980

6.6

1982

6.4

2000

7.1

2005

6.2

2003

6.6