Year	Percent
1991	13.308
1992	13.56
1993	13.181
1994	13.449
1995	13.357
1996	13.897
1997	14.331
1998	13.39
1999	14.438
2000	15.468
2001	18.143
2002	17.495
2003	16.758
2004	17.118
2005	17.023
2006	16.697
2007	16.493
2008	15.874
2009	22.236
2010	29.086
2011	35.813
2012	41.511
2013	42.642
2014	44.126
2015	45.367
2016	46.885
2017	47.885
2018	49.318
2019	50.707
2020	52.171
2021	53.628
2022	55