Year	Percent
1991	4.015
1992	4.153
1993	4.164
1994	4.016
1995	3.958
1996	4.108
1997	4.048
1998	4.406
1999	4.725
2000	4.975
2001	5.348
2002	5.751
2003	6.419
2004	6.897
2005	7.829
2006	9.136
2007	10.567
2008	12.053
2009	11.721
2010	11.457
2011	11.157
2012	10.877
2013	10.723
2014	10.623
2015	10.624
2016	10.597
2017	10.835
2018	11.136
2019	11.434
2020	11.695
2021	11.948
2022	12.191