Year	Percent
1991	32.828
1992	32.696
1993	33.58
1994	35.262
1995	33.809
1996	32.367
1997	34.591
1998	33.935
1999	32.977
2000	33.628
2001	33.191
2002	32.887
2003	31.9
2004	33.07
2005	31.483
2006	32.065
2007	31.611
2008	33.75
2009	29.187
2010	28.049
2011	28.093
2012	28.114
2013	28.512
2014	27.852
2015	27.702
2016	26.813
2017	25.726
2018	24.259
2019	23.566
2020	22.919
2021	22.121
2022	21.503