1963

6.5

2014

8.4

2008

8.1

2013

8.0

1978

7.6

2011

6.8

2000

8.2

2012

7.4

1997

7.9

1994

8.5

2015

7.7

1985

8.3

2010

8.2

2000

7.7

1972

8.7

2014

8.0

1990

7.4

2019

8.5

1999

8.0

2006

8.2