Year	Percent
1980	14.4186
1981	16.62557
1982	17.17782
1983	14.47948
1984	15.81262
1985	11.86858
1986	12.91955
1987	11.79619
1988	11.45935
1989	10.94186
1990	17.74597
1991	15.39057
1992	11.61803
1993	9.93443
1994	11.49163
1995	9.21832
1996	9.59258
1997	20.47684
1998	13.41156
1999	12.95862
2000	10.97048
2001	10.60325
2002	9.71057
2003	9.09563
2004	8.45219
2005	7.28369
2006	6.09628
2007	4.65178
2008	5.86963
2009	4.23579
2010	4.0325
2011	4.66137
2012	4.43014
2013	4.51542
2014	4.55872
2015	4.06198
2016	4.0549
2017	4.04318
2018	3.38611
2019	3.24282
2020	3.49024
2021	4.36805
2022	3.86129