1991

9.3

2008

6.5

1995

6.5

2008

5.4

2000

6.9

1992

6.6

2002

7.0

1988

7.1

2002

3.7

1991

6.1

2002

6.2

2002

6.6

2003

5.7

1997

6.3

1994

6.7

2002

6.7

1998

6.8

1964

6.8

2004

6.1

2006

4.8