Year	Percent
1965	32.87397
1966	31.46961
1967	32.72841
1968	25.80472
1969	39.97253
1970	37.07525
1971	29.35341
1972	22.29994
1973	23.0656
1974	19.03957
1975	17.66627
1976	15.76323
1977	15.83231
1978	16.91376
1979	9.9193
1980	9.36704
1981	8.91306
1982	8.03432
1983	7.24886
1984	5.94267
1985	6.32386
1986	9.18217
1987	12.04392
1988	15.057
1989	11.58717
1990	11.79926
1991	10.43163
1992	8.57599
1993	5.69366
1994	2.74588
1995	1.69274
1996	2.58925
1997	3.84724
1998	2.77875
1999	4.48654
2000	4.00691
2001	6.33962
2002	3.94442
2003	4.71127
2004	4.59221
2005	5.26483
2006	5.4192
2007	3.54264
2008	3.30802
2009	4.67739
2010	4.60842
2011	7.67905
2012	8.27846
2013	6.15017
2014	7.69098
2015	4.98261
2016	7.12139
2017	9.04256
2018	8.23068
2019	12.03402
2020	18.27463
2021	16.29489