Year	Percent
1991	46.769
1992	44.605
1993	45.451
1994	43.648
1995	45.231
1996	43.528
1997	40.162
1998	40.338
1999	40.852
2000	42.409
2001	42.202
2002	39.354
2003	39.6
2004	42.608
2005	41.235
2006	42.107
2007	39.694
2008	40.083
2009	37.608
2010	35.335
2011	32.224
2012	30.587
2013	25.189
2014	27.482
2015	26.578
2016	29.368
2017	28.608
2018	28.827
2019	29.193
2020	29.663
2021	29.434
2022	29.08