1996

6.6

2002

7.0

2001

6.7

1999

7.4

2003

5.8

1976

6.1

2006

5.4

2004

4.8

2001

6.1

1993

5.0

2003

5.0

1980

6.2

1984

6.0

1977

4.1

2007

5.2

1985

4.2

1993

5.7

1993

5.4

1979

4.3

1976

3.7