1979
1.5
4.8178
1980
5.0
6.5483
1981
3.9
8.205
1982
10.9
9.7879
1983
12.7
11.297
1984
14.2
12.7323
1985
17.5
14.0938
1986
14.9
15.3815
1987
22.4
16.5954
1988
14.0
17.7355
1989
21.8
18.8018
1990
20.8
19.7943
1991
21.8
20.713
1992
24.0
21.5579
1993
22.2
22.329
1994
22.6
23.0263
1995
22.9
23.6498
1996
24.5
24.1995
1997
22.2
24.6754
1998
27.0
25.0775
1999
25.3
25.4058
2000
28.4
25.6603
2001
26.1
25.841
2002
18.1
25.9479
2003
26.9
25.981
2004
21.5
25.9403
2005
25.7
25.8258
2006
26.2
25.6375
2007
24.0
25.3754
2008
26.0
25.0395
2009
24.2
24.6298
2010
21.8
24.1463
2011
24.5
23.589
2012
19.3
22.9579
2013
21.9
22.253
2014
22.6
21.4743
2015
27.9
20.6218
2016
21.8
19.6955
2017
17.5
18.6954
2018
24.1
17.6215
2019
9.3
16.4738