2009

6.2

1997

3.9

2014

6.3

2004

6.7

2001

6.0

2003

7.0

2005

6.0

2007

6.5

1991

7.1

2006

5.9

2002

6.1

2000

5.9

2002

6.6

1999

5.5

1996

3.0

1992

6.6

1962

7.2

1983

6.6

1990

5.1

1999

6.4