Year	Percent
1990	61.984
1991	62.17
1992	62.199
1993	62.11
1994	61.954
1995	61.678
1996	61.378
1997	61.088
1998	60.656
1999	60.498
2000	60.117
2001	59.832
2002	59.613
2003	59.445
2004	59.262
2005	59.085
2006	58.679
2007	58.177
2008	57.666
2009	57.26
2010	56.636
2011	55.9
2012	56.457
2013	56.197
2014	55.937
2015	55.649
2016	55.362
2017	55.035
2018	54.717
2019	54.402
2020	54.083
2021	53.74
2022	53.399
2023	53.072
2024	52.77
2025	52.504
2026	52.254
2027	52.042
2028	51.858
2029	51.691
2030	51.533