Year	% of total
1971	4.988495167970548
1972	4.981815106149032
1973	5.26059029189365
1974	6.122924103678411
1975	6.754431894681727
1976	6.8678101536130045
1977	7.401842294375123
1978	11.482633488854328
1979	14.177996793920322
1980	10.236890869935394
1981	13.154021821872622
1982	17.083544303797467
1983	7.087146422628952
1984	6.211460369980449
1985	2.8753702437912967
1986	5.339458047115344
1987	2.9365971801747253
1988	1.729503823581718
1989	2.2564102564102564
1990	7.149860767933483
1991	8.750669799266312
1992	3.7448347107438016
1993	4.899351189485943
1994	8.586691806112027
1995	9.009383986680792
1996	9.196982792488411
1997	9.308266475072847
1998	9.136483755635007
1999	10.866393880092511
2000	10.857847912202091
2001	8.472501255650428
2002	7.795231590711536
2003	7.732524365842639
2004	7.948128693368352
2005	6.966062771115081
2006	6.111804422258488
2007	5.797361250537788
2008	5.587621696801113
2009	7.600601875072341
2010	8.032333236236527
2011	11.135463800904978
2012	10.071307540242868
2013	8.392368661008627
2014	5.963606895535583
2015	6.0228296785821565