1993

5.4

2009

5.7

2001

6.0

2013

6.7

2006

7.0

2014

5.9

2004

5.7

1994

6.8

2017

5.9

2010

6.8

2017

7.4

1975

4.5

2012

6.2

1984

6.5

2011

6.0

2003

6.5

2021

6.2

1949

6.2

2013

6.8

1920

7.3