1955

7.2

1961

6.9

2005

5.4

2012

6.2

1982

6.7

1989

7.1

1994

6.5

1953

7.2

2012

6.9

1988

7.8

1965

7.1

2011

7.1

1997

4.6

2010

6.4

2013

6.8

1965

7.5

2006

5.9

2006

6.8

2012

6.0

1979

6.2