Year	Percent
1980	9.66686
1981	9.35809
1982	11.34333
1983	13.54851
1984	13.58882
1985	14.66948
1986	17.14558
1987	19.34056
1988	38.22292
1989	27.31623
1990	25.72052
1991	21.1373
1992	30.6932
1993	20.82102
1994	14.09102
1995	14.09823
1996	12.38071
1997	11.12263
1998	8.12446
1999	6.86407
2000	8.56714
2001	7.76459
2002	8.00545
2003	8.07339
2004	8.54182
2005	11.02528
2006	9.30148
2007	8.86633
2008	5.46262
2009	12.3488
2010	12.84475
2011	9.49949
2012	15.35882
2013	7.87851
2014	9.28937
2015	9.76265
2016	11.27875
2017	12.72113
2018	10.29694
2019	12.12299
2020	26.77677
2021	71.72772