2002

6.8

1983

5.0

2006

6.0

1992

7.1

1986

6.7

1999

6.5

1986

6.1

1983

7.3

1988

7.1

1974

6.9

2000

6.9

2000

6.3

1976

6.6

2000

5.1

1970

3.8

1980

6.3

1975

5.5

2004

1.0

2005

5.9

2007

6.4