1980

8.5

2011

7.8

2020

7.8

2014

8.3

7.2

1993

7.3

2013

7.0

1999

7.5

1966

7.6

1981

7.4

1991

7.3

1986

7.4

1989

7.7

2012

8.1

2008

7.5

2003

7.2

2017

8.0

2000

7.6

2001

7.5

2020

8.2