Year	Percent
1991	37.67
1992	38.918
1993	44.249
1994	45.843
1995	53.932
1996	59.406
1997	56.171
1998	51.041
1999	50.649
2000	50.126
2001	49.743
2002	48.667
2003	42.985
2004	38.686
2005	37.337
2006	35.363
2007	34.021
2008	33.584
2009	28.803
2010	27.921
2011	27.569
2012	29.581
2013	32.914
2014	34.459
2015	31.935
2016	27.818
2017	27.714
2018	27.117
2019	26.812
2020	26.087
2021	25.489
2022	24.993