Year	Percent
1970	13.28666
1971	18.25173
1972	22.49573
1973	32.4653
1974	40.98246
1975	42.2191
1976	87.3735
1977	105.09732
1978	131.94721
1979	116.94344
1980	123.05729
1981	138.27193
1982	161.33943
1983	175.90904
1984	192.05144
1985	230.60266
1986	238.35264
1987	243.76467
1988	231.64172
1989	214.04304
1990	220.02626
1991	159.53795
1992	150.57853
1993	184.02916
1994	182.04761
1995	178.65509
1996	167.48089
1997	175.73959
1998	170.6406
1999	177.35398
2000	182.83057
2001	181.85787
2002	165.1124
2003	145.49306
2004	123.13575
2005	103.21911
2006	53.89738
2007	52.16803
2008	50.57391
2009	61.48479
2010	62.77528
2011	56.02163
2012	65.64507
2013	63.406
2014	67.07012
2015	80.95847
2016	84.84731