1989

5.7

2000

5.5

1984

6.6

2003

5.8

2010

6.7

2001

4.9

1999

6.2

2006

5.5

1999

6.4

2003

6.3

2011

5.7

2010

5.9

1994

7.0

1985

5.8

2005

5.1

1998

6.0

2006

6.1

1995

5.2

1967

7.3

1977

6.5