Year	%
1971	49.29171
1972	43.68417
1978	48.3842
1979	43.85841
1980	43.90983
1981	45.1589
1982	50.6562
1983	44.84355
1985	43.88154
1987	43.06095
1988	61.01131
1989	38.83293
1991	39.32476
1995	44.35938
1996	42.49706
1998	45.4149
1999	48.46687
2000	55.19343
2001	52.98599
2002	55.54905
2003	64.21406
2004	64.52595
2005	64.55285
2006	78.60543
2007	75.03041
2008	71.83438
2009	79.33007
2010	94.65878
2011	92.87098
2012	91.96131
2013	90.8836
2014	89.99562
2015	76.50846
2016	72.97542