Year	% of total
1990	23.7431654676259
1991	23.01358620689655
1992	22.7354
1993	22.621103896103897
1994	22.048417721518987
1995	22.093105590062112
1996	21.912560975609754
1997	21.95808383233533
1998	21.65888888888889
1999	21.746162790697674
2000	21.792457142857142
2001	21.75338983050848
2002	21.594555555555555
2003	21.357252747252748
2004	21.962780748663103
2005	21.808999999999997
2006	21.390833333333333
2007	21.515561224489797
2008	22.07497512437811
2009	24.097428571428573
2010	24.276898148148145
2011	24.88914027149321
2012	26.055
2013	25.941222707423577
2014	24.922900432900434
2015	28.612466367713
2016	35.377665198237885