1969

6.6

2003

8.3

1995

7.3

1998

7.5

2005

7.2

2007

7.9

2005

6.6

2007

6.9

2002

5.9

2004

6.2

1978

6.3

1991

6.6

1994

7.6

1994

6.7

2008

5.9

1999

6.6

1998

7.9

2003

6.3

1993

5.7

2001

6.5