1989

5.2

1992

7.7

2008

6.3

2009

6.9

1988

5.2

1998

6.6

2004

6.7

2006

7.3

1987

6.2

2006

5.7

2011

4.7

1983

7.0

2007

5.9

2011

6.2

1998

7.5

2002

5.6

2006

6.2

1999

6.8

2006

5.1

1946

7.8