Year	Percent
1976	5.61716
1977	5.3061
1978	6.11184
1979	9.29368
1981	16.09353
1985	21.73403
1986	24.35796
1987	22.54578
1988	28.54041
1989	25.36132
1990	21.33749
1991	25.56879
1992	24.87355
1993	27.33406
1994	26.76666
1995	27.40429
1996	29.02372
1997	32.91552
1998	39.2198
1999	41.04616
2001	41.98603
2002	40.59097
2005	41.65269
2006	42.70162
2007	54.47884
2009	68.41483
2012	68.44688
2013	71.10951
2014	68.52172
2015	70.08937
2016	61.61822