2013

6.1

2007

5.2

1984

6.5

1972

6.2

2007

6.1

2009

6.6

6.0

1988

6.2

1962

7.6

2005

6.3

2003

5.7

2007

5.7

2002

5.5

1968

7.2

2002

6.7

2015

7.0

2010

6.4

2006

7.5

2011

6.6

1996

6.9