2003

8.5

2006

6.1

1998

6.1

1988

6.2

1967

6.6

1992

5.7

1987

4.1

1968

6.5

2011

7.5

1978

6.6

2008

8.7

1966

6.1

2015

5.1

2013

6.1

1989

6.2

2017

6.9

2004

6.4

2012

7.8

1996

5.5

1992

6.4