Year	Percent
1990	57.023
1991	56.84
1992	57.195
1993	57.003
1994	56.06
1995	55.801
1996	56.962
1997	57.028
1998	58.133
1999	58.32
2000	57.773
2001	58.895
2002	59.359
2003	59.554
2004	59.237
2005	59.459
2006	59.891
2007	60.101
2008	61.439
2009	61.64
2010	59.92
2011	60.587
2012	60.932
2013	61.261
2014	62.021
2015	62.395
2016	62.886
2017	62.868
2018	62.844
2019	62.798
2020	62.716
2021	62.587
2022	62.432
2023	62.249
2024	62.036
2025	61.791
2026	61.543
2027	61.275
2028	60.997
2029	60.718
2030	60.447