Year	Percent
1991	46.596
1992	46.603
1993	46.322
1994	46.621
1995	47.2
1996	47.127
1997	44.186
1998	42.56
1999	43.465
2000	39.335
2001	35.033
2002	32.533
2003	30.476
2004	28.819
2005	28.151
2006	27.224
2007	26.448
2008	26.037
2009	25.026
2010	23.82
2011	26.713
2012	26.49
2013	26.659
2014	27.578
2015	33.028
2016	34.388
2017	42.998
2018	46.247
2019	40.129
2020	37.495
2021	36.718
2022	35.914