Year	Percent
1977	18.36283
1978	25.09296
1979	30.20255
1980	28.16571
1981	28.64124
1982	31.76639
1983	34.70844
1984	37.7082
1985	36.36463
1986	58.80171
1987	56.222
1988	80.25958
1989	69.10308
1990	65.07955
1991	71.69113
2005	11.91023
2006	22.47937
2007	2.03866
2008	1.44438
2009	1.99652
2010	1.03762
2011	0.79097
2012	1.09339
2013	0.74719
2014	0.44276
2015	1.73016
2016	0.99515