2006

5.8

2004

6.1

1999

7.0

2002

7.0

2004

5.6

1996

4.5

2001

5.7

2007

6.6

2017

8.3

2001

6.4

1991

7.7

2014

5.3

2002

7.4

2000

7.1

2014

6.2

1988

5.4

2011

7.3

1967

5.9

1970

7.1

2005

6.7