1971

7.5

2017

5.2

2010

6.2

2000

6.3

2017

5.7

1941

6.0

2005

5.8

1961

1.0

1993

6.2

1991

8.3

1996

7.9

1965

6.4

2006

7.4

1992

2.5

2018

7.1

2013

6.0

2006

6.7

2017

4.4

1998

6.6

2004

5.8