Year	Percent
1991	28.822
1992	29.5
1993	27.293
1994	27.805
1995	28.296
1996	30.758
1997	30.226
1998	29.058
1999	29.612
2000	30.176
2001	31.25
2002	31.515
2003	31.848
2004	31.72
2005	30.821
2006	31.688
2007	32.705
2008	33.247
2009	33.119
2010	33.773
2011	34.46
2012	36.633
2013	35.889
2014	35.388
2015	34.196
2016	33.299
2017	33.853
2018	33.893
2019	33.91
2020	33.914
2021	34
2022	33.962