Year	% of total
1991	44.493987741304664
1992	34.13453883049267
1993	35.946442618609304
1994	37.01554407252195
1995	37.33672904856624
1996	38.86415421847078
1997	39.56034956873457
1998	39.94277834635849
1999	40.9449340477322
2000	40.86937201672934
2001	41.845720115063095
2002	41.507303524317905
2003	42.67714853231584
2004	43.232478795507596
2005	43.9361070073155
2006	42.05791234843643
2007	42.56970360273571
2008	42.086894883685396
2009	42.06229397716212
2010	44.03321352153682
2011	43.29215645103998
2012	42.432968562926625
2013	42.7096259931713
2014	43.84450301996307
2015	42.575571514496076
2016	42.33977509763406