1982

7.2

2006

5.0

1988

6.8

1998

5.3

2005

5.1

1977

6.2

1989

6.7

1999

5.7

1987

6.7

2001

6.0

2008

4.9

1976

7.2

2007

6.7

2006

6.1

2007

6.7

1982

7.8

2003

7.1

1998

7.3

2000

5.2

1993

6.9