Year	Percent
1991	49.596
1992	45.408
1993	43.915
1994	43.675
1995	39.654
1996	34.91
1997	36.666
1998	41.28
1999	41.989
2000	40.761
2001	41.447
2002	43.903
2003	47.11
2004	50.402
2005	52.393
2006	53.901
2007	55.005
2008	55.444
2009	59.139
2010	58.735
2011	58.702
2012	59.049
2013	56.047
2014	53.905
2015	57.285
2016	60.84
2017	60.862
2018	61.27
2019	61.756
2020	62.546
2021	63.15
2022	63.886