Year	Percent
1991	47.53
1992	48.822
1993	50.39
1994	51.157
1995	51.484
1996	52.651
1997	52.121
1998	51.573
1999	51.487
2000	51.99
2001	50.846
2002	51.582
2003	51.592
2004	51.904
2005	52.459
2006	52.565
2007	52.983
2008	54.912
2009	58.752
2010	60.859
2011	62.398
2012	64.018
2013	64.877
2014	65.522
2015	65.057
2016	65.212
2017	65.334
2018	65.574
2019	65.836
2020	66.094
2021	66.328
2022	66.484