Year	Percent
1968	4.935
1969	4.91925
1970	4.22586
1971	3.29253
1972	2.80963
1973	2.19317
1974	0.82975
1975	0.91528
1976	0.77447
1977	1.14745
1978	1.49965
1979	1.18428
1980	0.95364
1981	0.97182
1982	1.55233
1983	2.11026
1984	2.70133
1985	3.60336
1986	4.84256
1987	5.61441
1988	6.23076
1989	6.25643
1990	5.63589
1991	5.36542
1992	5.54248
1993	5.99871
1994	6.08589
1995	5.84875
1996	5.3678
1997	5.35196
1998	6.14068
1999	5.65434
2000	4.90087
2001	5.13491
2002	5.03757
2003	4.47188
2004	3.86832
2005	3.18543
2006	2.91994
2007	2.74278
2008	2.29269
2009	2.83044
2010	2.61907
2011	2.15516
2012	2.07093
2013	2.17
2014	2.28862
2015	2.77293
2016	2.94703
2017	2.86746
2018	2.48162
2019	2.55954
2020	2.96026
2021	2.67517
2022	2.40492