Year	Percent
1991	29.372
1992	27.742
1993	25.924
1994	23.815
1995	23.323
1996	22.902
1997	22.1
1998	22.886
1999	23.353
2000	25.23
2001	25.444
2002	25.523
2003	27.205
2004	26.586
2005	27.07
2006	26.686
2007	28.46
2008	28.83
2009	28.506
2010	27.149
2011	26.711
2012	25.987
2013	25.552
2014	25.825
2015	26.134
2016	26.179
2017	27.229
2018	27.818
2019	28.097
2020	28.32
2021	28.548
2022	28.787