Year	Percent
1980	31.4201
1981	22.97525
1982	34.25058
1983	40.07712
1984	27.89676
1985	47.6063
1986	51.5936
1987	39.81403
1988	32.4731
1989	26.12814
1990	25.08571
1991	15.03571
1992	16.31116
1993	16.51568
1994	22.71303
1995	11.78979
1996	13.58968
1997	8.84019
1998	9.37909
1999	22.17183
2000	5.40259
2001	8.71253
2002	9.04972
2003	5.46262
2004	2.8613
2005	4.46228
2006	2.81129
2007	7.20047
2008	6.38005
2009	9.54841
2010	9.11137
2011	9.96073
2012	10.97746
2013	18.03709
2014	10.2744
2015	7.72046
2016	8.69378
2017	10.02786
2018	8.93199
2019	8.81684
2020	18.28615
2021	14.6251