Year	% of total
1990	7.004419079694576
1991	8.245800321981298
1992	7.6825176723835895
1993	7.752548026529215
1994	7.831476698546804
1995	7.72450301678494
1996	7.93222523155805
1997	7.73694173629946
1998	9.104286513154996
1999	10.5061340965242
2000	10.819710972815884
2001	9.367059670973616
2002	9.461562861012673
2003	12.310390866757766
2004	11.834673156266783
2005	15.256126073491467
2006	15.461602797403895
2007	15.708353111844874
2008	15.889685050938343
2009	14.695020854099141
2010	13.329443346043584
2011	14.258725370244147
2012	13.611684173300077
2013	12.8759491713946
2014	13.451098937723197
2015	13.550256840765618
2016	13.53235098302297