Year	Percent
1976	29.5887
1977	32.62134
1978	28.74988
1979	29.18213
1980	35.65081
1981	34.84417
1993	22.24646
1994	20.8166
1995	21.84269
1996	22.58331
1997	20.83372
1998	20.56876
1999	18.52522
2000	19.47238
2001	22.12129
2002	20.4555
2003	21.30155
2004	22.02506
2005	26.3787
2006	30.25759
2007	25.99529
2008	29.48841
2009	26.82741
2010	26.24402
2011	25.64374
2012	26.44625
2014	27.12529