Year	% of total
1992	39.66127914474363
1993	39.04463044313668
1994	38.80418488457615
1995	39.054084334554005
1996	39.94895862335054
1997	39.71593676715248
1998	40.54085213628924
1999	40.341637286495946
2000	41.89365340170899
2001	40.7927408401539
2002	38.87782322447343
2003	38.000544326047596
2004	37.55684295550106
2005	36.1925325693828
2006	34.73011375704435
2007	33.63628327991869
2008	34.95080460271131
2009	35.895799676992496
2010	34.60796610299141
2011	33.47367195379565
2012	33.21879705169844
2013	33.79961690806224
2014	33.926389983763926
2015	34.894076217761445
2016	35.35205795935043