1996

5.9

2014

8.4

2000

8.2

1997

7.9

2013

8.0

1978

7.6

2017

7.3

1999

8.0

2002

6.6

2011

6.8

1975

7.7

2012

7.7

1994

8.3

2010

8.2

1984

7.3

1972

8.7

2016

7.6

2009

7.6

2015

7.7

2009

7.2