Year	% of total
1992	70.03624831913939
1993	57.62917974588938
1994	52.65435897435897
1995	43.48002840288399
1996	48.00337295690936
1997	47.038310108943506
1998	53.23154607768469
1999	43.29858947911294
2000	44.93701824543864
2001	29.150377066115702
2002	29.620666142145296
2003	37.001033779848576
2004	37.37995013200352
2005	39.971800818553895
2006	38.01145449224465
2007	41.68196655761541
2008	35.88899594320487
2009	36.78669053301512
2010	36.032260869565214
2011	35.963820028011206
2012	37.874053966189855
2013	37.978391207390885
2014	35.24275819797732
2015	36.08866024246192
2016	37.4896295162278