1992

6.3

1998

7.0

2014

5.6

2017

7.4

6.0

2019

8.1

2016

5.9

2018

8.0

2012

7.8

2018

7.5

2017

6.8

2001

7.9

1977

8.2

2013

6.9

2015

7.6

2017

8.1

2018

6.2

1994

8.7

2013

7.2

2017

7.2