2009

8.5

2014

6.0

2008

5.2

1982

5.7

1968

6.9

1987

8.0

2015

5.9

1987

5.5

2008

6.1

2011

5.0

2012

5.6

2000

9.4

1994

5.3

2006

6.3

2015

5.2

1996

5.9

1974

6.3

1994

7.4

1935

6.5

2016

6.8