Year	Percent
1991	36.914
1992	36.328
1993	35.914
1994	35.225
1995	35.03
1996	35.779
1997	35.974
1998	35.242
1999	35.479
2000	36.084
2001	35.589
2002	36.21
2003	37.019
2004	37.76
2005	37.356
2006	36.682
2007	35.9
2008	35.79
2009	34.949
2010	35.77
2011	35.836
2012	35.359
2013	35.267
2014	34.683
2015	35.189
2016	35.93
2017	37.237
2018	37.827
2019	38.037
2020	37.856
2021	37.64
2022	37.474