Year	Percent
1991	44.389
1992	50.564
1993	51.549
1994	50.795
1995	53.298
1996	55.471
1997	53.792
1998	52.961
1999	52.818
2000	51.775
2001	49.541
2002	46.818
2003	44.913
2004	44.914
2005	44.276
2006	43.119
2007	40.149
2008	39.103
2009	38.645
2010	32.152
2011	32.482
2012	34.094
2013	28.299
2014	26.193
2015	26.941
2016	27.926
2017	28.046
2018	27.421
2019	26.521
2020	25.57
2021	24.288
2022	22.865