Year	Percent
1991	51.498
1992	51.483
1993	51.537
1994	51.553
1995	51.516
1996	51.552
1997	51.682
1998	51.708
1999	51.895
2000	51.919
2001	52.072
2002	52.183
2003	52.367
2004	52.477
2005	52.591
2006	53.428
2007	54.321
2008	55.049
2009	55.736
2010	57.002
2011	58.136
2012	60.379
2013	60.371
2014	60.352
2015	60.297
2016	59.959
2017	59.533
2018	59.199
2019	58.987
2020	58.693
2021	58.472
2022	58.268