1964

5.6

2002

5.5

2001

6.2

1984

4.8

2003

6.2

2005

5.5

2006

5.5

2007

5.7

2010

6.4

2003

6.6

2002

5.3

2000

5.0

1983

5.0

1975

5.4

2002

5.3

1978

6.5

2004

6.7

2001

5.1

2003

6.1

1956

1.0