Year	Percent
1991	2.479
1992	3.036
1993	3.734
1994	4.642
1995	5.868
1996	7.907
1997	11.079
1998	16.123
1999	17.05
2000	18.115
2001	18.182
2002	18.176
2003	17.758
2004	15.19
2005	15.523
2006	15.637
2007	15.327
2008	15.288
2009	15.797
2010	16.022
2011	14.387
2012	12.471
2013	9.607
2014	11.155
2015	9.793
2016	9.309
2017	9.334
2018	9.152
2019	8.971
2020	8.775
2021	8.643
2022	8.455