Year	Percent
1975	15.71984
1976	15.90296
1977	13.212
1978	10.91807
1979	10.24135
1980	9.58832
1981	9.25799
1982	9.26919
1983	7.90006
1984	8.94272
1985	7.48887
1986	7.32713
1987	7.43175
1988	7.17471
1989	6.92986
1990	6.85918
1991	6.19135
1992	5.72368
1993	5.61273
1994	5.06752
1995	4.77611
1996	4.57822
1997	3.92035
1998	4.33454
1999	3.89894
2000	3.64726
2001	3.8608
2002	3.78826
2003	3.35291
2004	3.08332
2005	2.73853
2006	2.27597
2007	2.02354
2008	2.09331
2009	1.98882
2010	2.06308
2011	2.15128
2012	2.0069
2013	2.04147
2014	1.85045
2015	1.87427
2016	2.15333
2017	1.85817
2018	1.73354
2019	1.76524
2020	1.84906
2021	1.62501
2022	1.59168