1957

7.2

2010

5.6

2009

5.6

1987

7.1

2010

7.1

1986

6.8

2015

7.8

1947

7.5

2004

6.5

2015

8.0

2014

5.3

2006

6.2

2011

7.0

2013

7.0

1967

6.5

2003

6.4

1968

6.6

2004

6.4

2006

7.0

2009

6.1