Year	% of total
1992	30.94995920995152
1993	33.02091749744434
1994	33.50682790196427
1995	33.45909776709326
1996	33.49791403743587
1997	34.21921455676732
1998	36.41058673048291
1999	36.54373692493674
2000	36.0615136294855
2001	35.039476471783146
2002	37.8729161255768
2003	40.55163529062272
2004	40.52772676795711
2005	38.91253674136717
2006	38.74532347120283
2007	37.90703959615173
2008	37.6561351063117
2009	36.251673830448965
2010	37.03151335494994
2011	38.79698504389541
2012	38.636317095961175
2013	35.86503874413261
2014	35.87448192795953
2015	36.340668725378926
2016	32.54478958384795