Year	Percent
1981	16.74279
1982	18.03641
1983	18.41536
1984	17.20093
1985	16.4007
1986	18.66953
1987	16.41757
1988	16.62938
1989	15.51501
1990	12.47384
1991	11.81157
1992	25.55711
1993	25.70937
1994	27.48261
1995	32.54282
1996	38.477
1997	32.23688
1998	32.43337
1999	31.69783
2000	27.42253
2001	22.96889
2002	18.91913
2003	18.43952
2004	20.02978
2005	19.79796
2006	17.64367
2007	18.42797
2008	19.21512
2009	17.86444
2010	11.73256
2011	10.30736
2012	11.25802
2013	13.41406
2014	13.34122
2015	14.0792
2016	12.62784
2017	11.13723
2018	11.428
2019	11.55838
2020	12.96566
2021	13.16317
2022	13.02785