1999

7.4

1984

6.9

2006

7.9

2013

7.4

2007

6.8

1990

7.4

2005

6.8

2013

8.1

1968

6.7

1994

7.6

2014

8.3

2017

8.2

2012

6.8

2016

7.9

1984

8.1

1982

6.8

2018

7.8

2019

7.1

2010

6.8