1990

8.5

1992

5.0

1993

6.6

2012

7.4

2016

5.7

2011

8.3

2005

7.8

2002

7.2

2003

8.2

1973

8.1

2004

8.3

2011

7.1

2009

7.6

1970

6.2

2013

7.5

2004

8.6

1989

7.9

2001

8.3

1997

7.3