Year	Percent
1980	69.87265
1981	51.41153
1982	38.94144
1983	51.8186
1984	35.19138
1985	24.82826
1986	30.49276
1987	26.11135
1988	19.60433
1989	14.93174
1990	18.29536
1991	25.71374
1992	31.85376
1993	46.58918
1994	59.85391
1995	66.73973
1996	65.67158
1997	84.96046
1998	83.56196
1999	72.69568
2000	54.29343
2001	56.47039
2002	57.0285
2003	65.22571
2004	64.84109
2005	77.91006
2006	100.14615
2007	146.28459
2008	139.404
2009	155.22643
2010	137.47131
2011	114.47793
2012	118.40466
2013	117.14751
2014	119.71243
2015	112.27041
2016	104.73995