1992

6.3

1974

6.2

1973

4.8

2008

6.1

1981

6.7

2009

4.7

2007

5.5

1989

5.0

2006

5.4

1991

6.7

2000

4.4

2009

6.5

2009

5.3

1980

6.3

1979

6.7

2005

4.3

1997

5.2

1977

6.8

1976

4.8

2002

6.1