Year	Percent
1991	10.451
1992	11.263
1993	11.764
1994	11.992
1995	12.171
1996	12.409
1997	14.832
1998	13.901
1999	14.04
2000	14.637
2001	16.482
2002	17.536
2003	19.668
2004	20.759
2005	22.594
2006	24.211
2007	25.019
2008	24.772
2009	25.395
2010	25.649
2011	25.237
2012	25.075
2013	25.133
2014	25.137
2015	26.93
2016	28.466
2017	28.826
2018	29.232
2019	29.497
2020	29.752
2021	29.983
2022	30.17