Year	Percent
1991	1.587
1992	2.159
1993	3.081
1994	4.375
1995	6.386
1996	10.246
1997	10.693
1998	11.295
1999	12.016
2000	12.564
2001	15.204
2002	18.493
2003	22.898
2004	20.632
2005	19.298
2006	19.309
2007	19.279
2008	19.715
2009	20.311
2010	21.427
2011	21.144
2012	21.915
2013	22.762
2014	21.338
2015	20.652
2016	21.64
2017	23.222
2018	24.225
2019	25.158
2020	26.072
2021	27.011
2022	27.781