1974

6.0

2017

6.9

2016

6.0

2012

7.0

1978

6.1

2010

6.3

2002

5.2

2008

5.2

2006

6.8

2009

5.9

1980

6.2

1999

5.8

1979

4.7

1988

7.0

2016

7.9

2020

6.8

2004

6.4

2019

7.7

1990

4.7

1994

5.3