Year	% of total
1971	85.19515477792731
1972	79.67980295566502
1973	73.20028510334996
1974	83.80052151238591
1975	90.96418732782368
1976	90.814639905549
1977	94.19758412424504
1978	95.43795620437956
1979	95.47363509099394
1980	96.39196967569845
1981	95.50478997789241
1982	94.90208599404002
1983	97.7001370131141
1984	95.95778930423896
1985	94.73684210526315
1986	98.07410831214852
1987	96.07766074516584
1988	98.68967492481741
1989	98.52518924562777
1990	99.16169895678092
1991	98.31075237820698
1992	98.91173575412884
1993	98.18172452869064
1994	99.16511592817984
1995	99.0210499619579
1996	99.34637358380944
1997	99.65111410894544
1998	99.07574585160347
1999	99.18002989053602
2000	99.78750196757437
2001	99.74084507042254
2002	99.79383680555556
2003	99.10385174664367
2004	99.1968
2005	98.36355594869526
2006	99.38113893147107
2007	99.39240778578342
2008	99.29664976637837
2009	99.20521544894937
2010	99.61953907377443
2011	99.01999062939247
2012	98.91631966827535
2013	99.44898981466022
2014	99.60462003050964
2015	99.67731620105236