Year	% of total
1992	34.45031003937008
1993	29.993153360137853
1994	35.554858557284305
1995	48.29928336079078
1996	64.48983653846155
1997	36.21066805845511
1998	36.0764971098266
1999	35.47261224489796
2000	26.12259314456036
2001	27.371908831908833
2002	26.81302228412256
2003	26.476023166023165
2004	27.054730077120826
2005	28.914608801955993
2006	29.593333333333334
2007	26.759189189189186
2008	25.06158282208589
2009	24.57465968586387
2010	23.90177108433735
2011	22.968155688622755
2012	22.434471744471743
2013	24.004038997214487
2014	22.73444876783398
2015	20.986945137157107
2016	21.21814496314496