Year	Percent
1991	28.423
1992	28.917
1993	28.575
1994	28.66
1995	29.125
1996	29.091
1997	28.858
1998	28.724
1999	28.332
2000	28.197
2001	27.918
2002	27.463
2003	27.322
2004	27.982
2005	26.739
2006	26.449
2007	26.168
2008	25.497
2009	25.022
2010	25.334
2011	25.103
2012	24.973
2013	24.884
2014	24.74
2015	24.441
2016	23.997
2017	23.823
2018	23.685
2019	23.58
2020	23.509
2021	23.435
2022	23.359