Year	Percent
1973	8.36892
1982	35.00257
1983	27.33424
1984	32.40584
1985	32.91753
1986	44.27454
1987	33.25866
1988	26.32823
1989	26.04765
1990	27.25813
1991	27.44776
1992	25.50901
1993	25.2035
1994	25.47065
1995	25.89396
1999	14.19392
2000	16.35605
2001	19.06736
2002	22.33138
2004	29.06875
2005	40.61596
2006	40.02852
2007	44.08338
2008	56.38545
2009	53.56146
2010	57.19876
2011	53.42409
2012	50.90841
2013	48.64401
2014	48.10355
2015	48.3696