2000

5.2

1990

6.2

2006

5.4

1991

5.5

1991

5.3

2008

5.1

2002

5.4

2002

7.6

2007

7.5

1965

6.6

1994

6.5

1997

5.0

1997

5.6

2001

5.0

1950

7.0

1996

5.3

2005

6.7