Year	Percent
1991	10.283
1992	10.105
1993	9.815
1994	9.694
1995	9.721
1996	9.46
1997	9.384
1998	8.802
1999	7.337
2000	8.644
2001	8.79
2002	8.2
2003	8.15
2004	7.653
2005	7.912
2006	7.63
2007	8.023
2008	8.827
2009	9.99
2010	10.181
2011	12.769
2012	13.785
2013	15.256
2014	15.938
2015	15.883
2016	17.802
2017	19.316
2018	19.485
2019	20.079
2020	20.609
2021	21.484
2022	22.084