Year	Percent
1991	3.365
1992	3.32
1993	3.342
1994	3.345
1995	3.415
1996	3.523
1997	3.871
1998	3.471
1999	5.372
2000	9.612
2001	12.161
2002	11.942
2003	12.038
2004	11.678
2005	10.812
2006	11.064
2007	10.38
2008	9.069
2009	12.88
2010	15.535
2011	19.704
2012	25.619
2013	25.666
2014	25.822
2015	26.315
2016	26.181
2017	25.921
2018	25.458
2019	25.077
2020	24.572
2021	24.095
2022	23.535