Year	% of total
1972	100
1973	100
1974	100
1975	100
1976	100
1977	100
1978	100
1979	100
1980	100
1981	100
1982	100
1983	100
1984	100
1985	100
1986	100
1987	100
1988	100
1989	100
1990	62.24765124555161
1991	62.767262773722635
1992	59.005363636363626
1993	59.23615384615385
1994	63.45814935064935
1995	61.95965517241378
1996	54.377089041095886
1997	55.42306188925081
1998	55.005
1999	41.325
2000	50.95583126550869
2001	51.83072351421188
2002	51.86575682382134
2003	46.02459183673469
2004	49.97095717884131
2005	50.03570093457943
2006	51.19454767726162
2007	44.818888888888885
2008	44.521890660592256
2009	38.55281173594132
2010	59.08548961424332
2011	35.75325
2012	45.39074074074074
2013	49.92660071942446
2014	53.95067321178121
2015	40.23019417475729
2016	50.21523876404495