Year	Percent
1991	34.127
1992	34.077
1993	34.063
1994	34.076
1995	34.093
1996	34.134
1997	34.2
1998	33.955
1999	33.686
2000	33.398
2001	33.135
2002	32.862
2003	32.571
2004	32.262
2005	33.868
2006	35.484
2007	36.808
2008	39.301
2009	41.877
2010	44.36
2011	48.344
2012	50.689
2013	52.941
2014	56.565
2015	55.275
2016	55.259
2017	55.484
2018	55.703
2019	55.921
2020	56.194
2021	56.479
2022	56.772