1961

7.6

1974

7.8

2004

6.1

2001

6.9

1976

7.0

1983

4.2

1992

4.4

2003

6.6

2009

5.9

2002

5.9

2008

7.5

1983

5.0

1979

5.3

2005

6.0

1999

5.2

2004

6.5

1995

6.4

1976

5.6

1978

6.9

1971

4.6