2003

7.1

1982

7.8

1993

6.9

2006

5.0

1992

6.7

1993

6.1

1999

5.7

1994

6.0

2008

4.9

1987

6.7

2001

6.0

1997

6.4

2002

5.9

1982

7.2

1999

6.0

2005

5.1

1977

6.2

1991

6.3

2006

6.1

2007

6.7