Year	Percent
1991	27.999
1992	27.751
1993	27.62
1994	27.429
1995	27.007
1996	26.876
1997	26.944
1998	26.724
1999	26.829
2000	26.456
2001	26.618
2002	26.6
2003	26.71
2004	26.633
2005	26.542
2006	27.4
2007	28.459
2008	29.099
2009	29.702
2010	30.983
2011	32.53
2012	35.416
2013	35.484
2014	35.407
2015	35.479
2016	35.048
2017	34.658
2018	34.437
2019	34.333
2020	34.17
2021	34.084
2022	34.012