1971

8.1

1993

7.1

1994

7.8

2006

8.0

1994

8.4

2007

7.5

1991

6.8

2016

5.3

2005

8.1

1998

5.5

2014

6.5

1996

4.2

2010

6.0

2015

4.3

2014

7.7