Year	% of total
1971	0
1972	0
1973	0
1974	0
1975	0
1976	0
1977	0
1978	0
1979	0
1980	0
1981	0
1982	0
1983	0
1984	0
1985	0
1986	0.7988721804511277
1987	0.7137459064573013
1988	0.6482116983146496
1989	0.6013016411997737
1990	0.5409189257986509
1991	1.4479049701554283
1992	1.3862170419825732
1993	1.2920577998101468
1994	1.175116312532975
1995	1.1014206078043518
1996	1.016597510373444
1997	0.9108483902148858
1998	0.8634361233480177
1999	0.8299457994579946
2000	0.7737249328912048
2001	1.4294780742845055
2002	1.3645280406185092
2003	1.4009962640099627
2004	1.3012414767324985
2005	1.2508832072854787
2006	1.2093707215658436
2007	1.183964213648409
2008	1.2584797564542032
2009	1.29826008881555
2010	1.3050858667136966
2011	1.3277413186144553
2012	1.3582848991931191
2013	1.5468323292126165
2014	1.6626164439044147
2015	1.8208866408806903