Year	Percent
1962	3.94379
1963	0.43478
1964	0.44562
1965	1.35234
1966	1.38229
1967	1.33261
1968	1.41422
1969	1.75449
1971	1.03241
1972	1.45867
1973	1.94621
1974	2.22508
1975	2.05681
1976	2.2236
1977	2.53338
1978	2.79637
1979	2.64372
1980	2.9188
1981	3.03033
1982	3.50702
1983	3.10481
1984	2.9754
1985	2.75117
1986	2.80541
1987	2.64914
1988	3.14525
1989	3.34952
1990	3.44871
1991	3.78627
1992	3.59564
1993	3.72028
1994	3.92111
1995	4.20907
1996	5.85688
1997	6.35965
1998	6.57227
1999	6.25764
2000	5.96823
2001	8.03664
2002	7.15013
2003	7.29044
2004	6.59999
2005	4.43619
2006	3.51172
2007	3.4146
2008	2.72089
2012	2.53359
2013	2.48241
2014	2.18149
2015	2.33428
2016	2.24286
2017	1.98315