Year	Percent
1980	54.1438
1981	63.38187
1982	45.31137
1983	48.49299
1984	53.64125
1985	48.26863
1986	34.19087
1987	42.93734
1988	44.33674
1989	42.67187
1990	48.87448
1991	44.86134
1992	69.12772
1993	90.57468
1994	100.75882
1995	92.2591
1996	94.79905
1997	99.41978
1998	86.40949
1999	134.34265
2000	120.06009
2001	108.69439
2002	96.72452
2003	105.6315
2004	98.30021
2005	114.97602
2006	97.24888
2007	96.0434
2008	100.85291
2009	84.09828
2010	81.50359
2011	84.0782
2012	83.22294
2013	75.715
2014	69.24171
2015	52.49759
2016	41.79313
2017	42.36748