Year	Percent
1990	51.509
1991	51.131
1992	50.901
1993	50.74
1994	50.534
1995	50.259
1996	51.068
1997	51.967
1998	52.973
1999	54.172
2000	55.599
2001	57.943
2002	60.275
2003	62.382
2004	64.099
2005	65.369
2006	66.194
2007	66.741
2008	67.023
2009	67.111
2010	64.557
2011	62.27
2012	63.503
2013	58.187
2014	54.931
2015	57.765
2016	57.571
2017	58.034
2018	58.484
2019	58.901
2020	59.273
2021	59.596
2022	59.876
2023	60.13
2024	60.382
2025	60.649
2026	60.92
2027	61.203
2028	61.489
2029	61.757
2030	61.995