Year	Percent
1981	5.24309
1982	3.824
1983	7.44046
1984	93.34204
1985	15.38233
1986	12.84519
1987	12.61595
1988	15.46195
1989	24.63639
1990	21.81272
1991	18.04936
1992	13.63548
1993	22.69974
1994	28.67846
1995	29.32825
1996	34.78379
1997	41.21947
1998	30.11115
1999	39.25164
2000	38.39352
2001	39.9219
2002	32.83712
2003	41.93175
2004	53.49947
2005	61.89339
2006	81.3061
2007	88.49044
2008	31.5436
2009	58.77393
2010	68.81077
2011	44.29078
2012	47.57958
2013	50.69265
2014	43.93205
2015	50.14591
2016	62.32084
2017	72.00832