1990

7.7

2006

8.0

1997

7.9

2004

8.1

1994

8.3

2003

7.2

2016

5.6

1970

6.8

2011

5.9

1995

7.1

1980

7.5

2009

7.0

2005

6.5

2001

6.8

2000

6.7

2016

6.5

2012

0.0

2008

6.2

1936

0.0

1934

6.1