Year	% of total
1990	43.80060695413908
1991	43.28708055299772
1992	40.565999658612455
1993	40.33622477309887
1994	40.5495049556481
1995	40.26326787572805
1996	40.43647569632607
1997	39.44230562612964
1998	38.143974576963195
1999	37.88818285299983
2000	37.79382822010695
2001	37.340547180400016
2002	38.548621656653395
2003	39.697517559975175
2004	40.65588174117123
2005	41.57368897541534
2006	42.74781490529684
2007	41.920727649366526
2008	44.49113293605746
2009	42.80029768764446
2010	44.33938713209009
2011	45.80555029042558
2012	45.8687397844763
2013	44.619814200224056
2014	44.57559569631788
2015	44.56084157274169
2016	43.2504412823731