Year	Percent
1991	6.667
1992	6.666
1993	6.694
1994	6.326
1995	6.724
1996	7.035
1997	7.433
1998	7.858
1999	8.565
2000	9.089
2001	9.351
2002	9.855
2003	10.488
2004	11.312
2005	11.902
2006	12.869
2007	17.285
2008	20.69
2009	25.536
2010	30.935
2011	36.589
2012	41.633
2013	46.032
2014	45.128
2015	46.04
2016	46.926
2017	47.732
2018	48.596
2019	49.424
2020	50.126
2021	50.832
2022	51.561