1987

7.8

2006

8.2

1993

8.6

2017

7.8

1983

8.2

1994

8.5

1979

8.2

1995

8.4

2000

8.2

2016

7.6

2014

7.4

1989

7.8

2010

8.4

1976

8.1

1996

7.9

2001

7.5

2017

7.6

2014

7.9

2004

7.2

2016

7.0