Year	Percent
1991	54.561
1992	49.567
1993	47.314
1994	43.24
1995	38.994
1996	37.781
1997	36.28
1998	33.994
1999	32.533
2000	35.289
2001	34.145
2002	36.066
2003	28.072
2004	26.041
2005	28.516
2006	26.047
2007	26.522
2008	27.652
2009	29.273
2010	22.544
2011	22.839
2012	23.81
2013	24.85
2014	23.202
2015	29.63
2016	24.746
2017	25.334
2018	25.524
2019	25.686
2020	25.726
2021	25.664
2022	25.582