Year	Percent
1991	2.63
1992	2.684
1993	2.721
1994	2.792
1995	3.068
1996	3.29
1997	3.834
1998	3.972
1999	4.429
2000	4.782
2001	5.302
2002	5.999
2003	6.863
2004	7.506
2005	8.421
2006	8.134
2007	7.844
2008	7.393
2009	7.229
2010	7.056
2011	8.079
2012	8.109
2013	7.99
2014	8.384
2015	8.814
2016	8.88
2017	9.136
2018	9.221
2019	9.278
2020	9.324
2021	9.377
2022	9.364