Year	Percent
1961	1.31547
1962	1.66769
1963	3.0258
1964	4.64243
1965	5.10071
1966	4.08601
1967	3.19343
1968	2.62029
1969	4.02383
1970	7.24242
1971	5.35822
1972	6.31782
1973	6.80699
1974	12.16834
1975	12.88972
1976	7.57526
1977	7.47806
1978	4.42325
1979	4.50524
1980	4.1266
1981	5.1392
1982	7.57042
1983	5.61285
1984	5.43872
1985	4.62774
1986	2.79678
1987	1.68411
1988	2.16899
1989	4.79746
1990	2.8124
1991	2.87662
1992	3.42452
1993	3.99323
1994	2.09431
1995	1.22077
1996	0.44407
1997	0.89923
1998	1.76078
1999	0.56859
2000	2.02358
2001	2.10159
2002	1.67984
2003	1.96281
2004	1.9806
2005	2.13603
2006	2.30988
2007	2.0075
2008	1.91522
2009	0.7781
2010	1.88309
2011	2.00185
2012	1.97467
2013	1.0462
2014	0.66545
2015	1.11479
2016	1.58444
2017	1.67799