Year	% of total
1990	1.5843659453794463
1991	2.3192450824029773
1992	1.9990737882062366
1993	3.2308089945722407
1994	2.9315617420647473
1995	4.249180327868853
1996	4.979591836734694
1997	5.921562548442102
1998	5.844961240310077
1999	6.236559139784946
2000	6.724937566892615
2001	6.292772492071441
2002	6.507854306922148
2003	6.313850276335622
2004	6.470992104359767
2005	6.2938230383973295
2006	6.18844386080105
2007	6.383338977311209
2008	6.4596479574892065
2009	5.776056792513714
2010	6.657942090626534
2011	6.083650190114068
2012	4.6363322992071705
2013	6.902694277443776
2014	5.924126331526818
2015	5.056640945657528