1980

5.0

2010

6.3

2011

6.2

2003

0.0

2000

7.3

1978

7.1

1964

7.0

1976

6.8

1997

6.5

2005

4.3

1989

6.7

2004

7.6

1990

6.9

1977

8.3

2002

6.9

1996

7.3

2015

6.0

2012

7.4

2014

7.8

2011

0.0