Year	% of total
1990	11.802929427430094
1991	11.134496446044494
1992	12.337215925831353
1993	14.970803068221123
1994	14.97071129707113
1995	13.04027142646408
1996	14.366234395297123
1997	12.54397012203066
1998	12.544662309368192
1999	12.545182050603898
2000	12.544810515534314
2001	12.54560997477117
2002	12.545122693165686
2003	15.425101214574898
2004	18.02
2005	17.540650406504067
2006	17.98900235663786
2007	13.074565883554648
2008	22.995951417004047
2009	18.67867867867868
2010	20.97872340425532
2011	19.541984732824428
2012	21.352380952380955
2013	21.328413284132843
2014	21.353790613718413
2015	20.652932960893857