1960

6.9

2005

6.7

2004

5.6

2009

2.2

1972

7.7

2006

7.3

1984

6.8

1997

6.4

2005

5.8

2008

5.9

2000

5.5

1992

4.7

2001

6.6

1994

7.1

2004

6.4

1985

6.2

1989

5.9

2003

6.0

2003

6.1

2006

6.8