Year	Percent
1990	60.259
1991	60.492
1992	61.552
1993	62.371
1994	62.784
1995	62.931
1996	62.46
1997	60.008
1998	59.189
1999	58.556
2000	57.483
2001	57.686
2002	57.738
2003	59.178
2004	59.189
2005	59.238
2006	59.286
2007	59.291
2008	59.369
2009	59.422
2010	59.279
2011	59.028
2012	58.692
2013	58.228
2014	57.979
2015	57.702
2016	57.477
2017	57.405
2018	57.333
2019	57.272
2020	57.227
2021	57.192
2022	57.172
2023	57.171
2024	57.188
2025	57.225
2026	57.271
2027	57.336
2028	57.413
2029	57.496
2030	57.579