Year	Percent
1977	10.51191
1978	20.30584
1979	22.22645
1980	27.46862
1981	37.30087
1982	27.72671
1983	23.7408
1984	25.42833
1985	14.8789
1986	39.68472
1987	8.97455
1988	11.81152
1989	4.18824
1990	10.11708
1991	6.83534
1992	16.97529
1993	17.48228
1994	73.0334
1995	64.27036
1996	59.49569
1997	31.93204
1998	44.4924
1999	87.79438
2000	76.35194
2001	112.75365
2002	13.48494
2003	10.55992
2004	10.46387
2005	6.87025
2006	7.83537
2007	2.85416
2008	1.6983
2009	2.09346
2010	2.72316
2011	3.40792
2012	1.66829
2013	1.54784
2014	2.32493
2015	6.64997