Year	Percent
1969	5.62686
1970	5.16785
1971	4.80212
1972	4.74713
1973	4.6761
1974	4.04059
1975	4.32649
1976	4.32051
1977	3.65923
1978	3.53213
1979	3.49788
1980	3.44503
1981	3.86697
1982	3.97434
1983	3.80204
1984	3.77829
1985	3.79939
1986	3.92302
1987	3.87669
1988	3.82965
1989	4.14441
1990	4.01224
1991	3.90049
1992	3.63832
1993	3.18594
1994	3.21275
1995	3.10426
1996	2.87733
1997	2.96792
1998	2.55697
1999	2.32967
2000	2.29864
2001	2.22462
2002	2.07768
2003	2.05983
2004	1.86629
2005	1.85793
2006	1.94595
2007	1.81711
2008	1.63505
2009	1.55319
2010	1.77851
2011	1.57897
2012	1.6595
2013	1.79086
2014	1.73834
2015	1.72433
2016	1.76653
2017	1.85559
2018	1.65067
2019	1.63581
2020	1.59906
2021	1.51691
2022	1.50498