Year	Percent
1991	38.385
1992	35.261
1993	38.381
1994	39.877
1995	39.116
1996	39.206
1997	39.351
1998	39.607
1999	40.774
2000	46.193
2001	46.858
2002	45.724
2003	47.112
2004	53.577
2005	51.184
2006	50.413
2007	54.04
2008	53.742
2009	55.45
2010	55.474
2011	55.751
2012	57.94
2013	53.966
2014	55.461
2015	58.049
2016	59.181
2017	60.25
2018	60.86
2019	61.48
2020	62.07
2021	62.661
2022	63.137