Year	% of total
1971	98.81114130434783
1972	98.92761394101876
1973	99.02813299232737
1974	99.24555853005597
1975	99.0220661985958
1976	98.88651978204217
1977	98.85264341957254
1978	98.62178637688842
1979	98.86848847139197
1980	99.22888847094225
1981	99.34895833333334
1982	99.43650633930369
1983	99.06687402799378
1984	98.19868995633188
1985	98.97282968853546
1986	99.31849159472966
1987	100
1988	100
1989	100
1990	100
1991	100
1992	100
1993	99.65151275146523
1994	99.5417348608838
1995	99.68933943754088
1996	99.96982043156783
1997	99.49172233517281
1998	77.53036437246963
1999	83.58667529107375
2000	91.49937699017029
2001	84.09466853289223
2002	69.24240340987214
2003	66.06596395783747
2004	87.44825302202351
2005	82.92575132586919
2006	66.65480427046263
2007	53.410719403840645
2008	74.42335415665545
2009	76.76936816253628
2010	68.81085866037179
2011	67.50892857142857
2012	67.12408516300732
2013	63.96550384585502
2014	64.69952942991591
2015	50.86589504829867