1980

5.2

1978

5.0

2008

5.9

1996

6.2

2002

6.9

1985

8.1

2006

6.8

2008

6.3

1999

6.0

2005

5.2

1965

8.3

2018

6.9

2006

7.0

2017

4.9

2010

7.0

2015

6.0

1986

6.5

1982

4.6

1987

8.0

2014

5.1