2005

4.7

2001

4.8

2006

6.8

1999

7.3

2007

5.7

2016

6.4

1958

5.9

1992

6.2

1995

6.8

1972

5.9

1958

5.9

1965

5.2

2011

6.7

2004

7.0

1994

6.3

2006

5.1

2005

6.5

2001

6.9

2002

7.1

1998

6.5