Year	Percent
1991	9.132
1992	8.252
1993	8.843
1994	9.287
1995	9.787
1996	10.596
1997	10.486
1998	11.099
1999	12.197
2000	12.807
2001	13.597
2002	14.283
2003	14.422
2004	15.36
2005	16.209
2006	16.584
2007	17.503
2008	18.215
2009	19.124
2010	21.438
2011	23.053
2012	24.038
2013	27.393
2014	28.614
2015	29.935
2016	30.866
2017	31.467
2018	32.545
2019	33.443
2020	34.355
2021	35.233
2022	36.145