2001

4.3

2019

6.7

2009

8.5

2003

6.6

2004

6.7

2015

5.4

2017

6.9

2018

6.0

2023

7.8

2016

6.8

2010

6.7

2013

6.1

1978

7.8

2008

6.1

1985

6.1

1970

7.7

1952

7.0

1989

7.1

1993

5.4