Year	Percent
1970	22.96272
1971	19.43886
1972	12.94901
1973	14.43806
1974	3.08012
1975	4.4667
1976	1.53543
1977	1.66545
1978	5.1908
1979	3.671
1980	4.71603
1981	3.07487
1982	4.88213
1983	5.31833
1984	6.4121
1985	4.33149
1986	4.98389
1987	9.50851
1988	7.35852
1989	11.9921
1990	10.1706
1991	9.9794
1992	5.46288
1993	10.26104
1994	19.7538
1995	12.4389
1996	8.94121
1997	2.36971
1998	2.51701
1999	3.91727
2000	1.06495
2001	0.75619
2002	5.34945
2003	-0.74072
2004	2.39719
2005	2.45687
2006	1.2568
2007	1.71715
2008	1.64123
2009	2.29972
2010	2.48945
2011	1.43147
2012	1.48697
2013	1.6985
2014	1.73949
2015	2.34949
2016	1.09991
2017	3.34458
2018	3.60152
2019	3.13453
2020	1.74601
2021	2.85939