Year	Percent
1977	24.68057
1978	25.8352
1979	22.56619
1980	21.46029
1981	20.87536
1982	19.62078
1983	18.76183
1984	18.27027
1985	18.37941
1986	20.11747
1987	19.75718
1988	18.87135
1989	15.49084
1990	16.34244
1991	15.68188
1992	14.82214
1993	14.16008
1994	14.40579
1995	12.16659
1996	12.97186
1997	12.54416
1998	12.06534
1999	12.13732
2000	11.904
2001	11.29498
2002	10.84001
2003	11.03847
2004	11.19785
2005	11.48766
2006	10.50129
2007	10.44642
2008	11.56486
2009	12.55206
2010	11.46603
2011	12.50102
2012	12.0196
2013	13.98469
2014	13.449
2015	14.05558
2016	16.27181
2017	13.40515
2018	11.02358
2019	11.98316
2020	15.15594
2021	16.95815
2022	15.81864