Year	% of total
1990	63.614200921596606
1991	61.60956902830171
1992	52.493172762347506
1993	53.00305477860664
1994	55.24649482368213
1995	55.352104973704144
1996	56.70773413826198
1997	54.96437323621991
1998	51.268427687154755
1999	51.335513282448474
2000	49.59249412392699
2001	48.34808780682647
2002	50.809830560368006
2003	53.652740070993815
2004	54.793549444310386
2005	56.332696576169035
2006	57.388473251721024
2007	54.790951862126796
2008	60.07568023208315
2009	56.803879421867826
2010	60.23032900023621
2011	61.66638141634738
2012	61.46811496108853
2013	59.58393518475578
2014	59.49715904422273
2015	58.912150633511956
2016	56.990973736301584