Year	Percent
1991	3.874
1992	4.008
1993	3.952
1994	4.04
1995	4.323
1996	4.693
1997	4.786
1998	4.751
1999	4.971
2000	4.276
2001	4.571
2002	5.114
2003	5.45
2004	5.793
2005	6.433
2006	6.631
2007	7.503
2008	8.213
2009	8.836
2010	9.951
2011	10.333
2012	11.25
2013	11.455
2014	11.677
2015	11.798
2016	12.066
2017	12.236
2018	12.514
2019	12.835
2020	13.087
2021	13.365
2022	13.627