2018

6.7

2016

5.6

1984

6.7

1975

4.5

2014

5.6

2015

6.8

5.7

2013

6.9

2016

7.0

2010

7.2

2011

6.2

2010

5.2

2021

7.7

1992

6.9

2013

6.1

1971

7.4

1976

7.4

2015

7.9

2023

7.6

2017

10.0