Year	% of total
1990	46.76126998746689
1991	45.27460253271308
1992	44.41562545264252
1993	44.58860867516505
1994	44.717531678207486
1995	44.450786581168636
1996	44.368682647403574
1997	43.7177856115189
1998	43.78935418726345
1999	43.82246103714372
2000	42.981619540389566
2001	42.91710269285236
2002	43.09131647324577
2003	42.977911659330225
2004	42.97854583082819
2005	42.920782460916996
2006	42.56585150394725
2007	41.31401111309353
2008	41.177937049379814
2009	42.3372595872816
2010	40.675010701607356
2011	40.30539111125809
2012	40.22168967196945
2013	39.85735560248798
2014	40.45622120843312
2015	41.09972211435715
2016	41.15134564937451