Year	Percent
1991	15.515
1992	14.825
1993	16.45
1994	20.139
1995	19.877
1996	19.41
1997	20.633
1998	17.684
1999	20.168
2000	18.925
2001	20.318
2002	20.55
2003	19.218
2004	20.215
2005	20.424
2006	20.509
2007	21.029
2008	20.758
2009	20.628
2010	20.923
2011	22.98
2012	24.26
2013	24.09
2014	24.998
2015	25.749
2016	25.291
2017	25.369
2018	25.405
2019	25.009
2020	25.099
2021	25.088
2022	25.24