1978

8.0

2010

7.6

2007

6.7

2003

7.2

1997

8.4

1994

8.2

2019

6.9

2005

8.5

2018

8.0

1996

9.7

1995

6.3

1988

7.8

2004

7.8

2006

7.2

2002

8.1

2006

8.1

1976

7.4

2019

7.8

2017

8.7

2004

7.9