1990
6.4
1999
6.7
1997
5.3
1998
6.1
2002
5.4
1998
6.6
2012
5.3
2018
6.7
1978
7.7
2013
6.4
2000
7.2
2013
5.8
1984
7.2
2001
6.6
2014
6.2
1988
7.4
2005
4.7
2001
6.4
2015
6.0
2014
8.0
2006
7.2
2001
6.9
2006
6.9
1998
6.1
2005
3.8
1995
7.2
1999
6.5
2014
6.7