Year	Percent
1990	54.748
1991	54.443
1992	54.137
1993	53.875
1994	53.892
1995	54.018
1996	53.163
1997	52.221
1998	51.203
1999	50.048
2000	50.78
2001	50.074
2002	49.975
2003	49.798
2004	49.35
2005	48.546
2006	48.438
2007	48.361
2008	48.342
2009	48.425
2010	48.389
2011	48.228
2012	47.462
2013	48.355
2014	47.017
2015	47.341
2016	47.207
2017	46.937
2018	46.643
2019	46.33
2020	46
2021	45.609
2022	45.206
2023	44.802
2024	44.414
2025	44.05
2026	43.686
2027	43.356
2028	43.046
2029	42.744
2030	42.442