Year	Percent
1977	10.46279
1978	8.63115
1979	8.04431
1980	8.4235
1981	5.77381
1982	8.15465
1983	6.30969
1984	6.64839
1985	4.93127
1986	5.84668
1987	5.91096
1988	5.4432
1989	4.25164
1990	3.49983
1991	3.78699
1992	3.98458
1993	3.85317
1994	3.23366
1995	2.89694
1996	2.78268
1997	3.0509
1998	2.26455
1999	1.7516
2000	1.54558
2001	1.73632
2002	1.78559
2003	1.78005
2004	1.78207
2005	1.66097
2006	1.18856
2007	1.15525
2008	1.22395
2009	1.1222
2010	1.26847
2011	1.33469
2012	1.16489
2013	1.0833
2014	0.93684
2015	0.84908
2016	0.78902
2017	0.90146
2018	0.91608
2019	0.90054
2020	1.12712
2021	1.23932
2022	1.22161