1995

7.0

1985

7.0

1996

6.9

2006

6.9

2003

6.0

2002

5.9

2004

6.8

2006

6.4

1955

7.3

1988

6.2

2005

7.0

2010

8.0

1994

4.6

2012

0.0

1964

6.4

2014

6.5

2013

5.4

2015

4.8

1986

5.8

2017

5.9