Year	Percent
1990	46.021
1991	46.06
1992	46.052
1993	46.028
1994	45.97
1995	45.871
1996	45.969
1997	45.969
1998	45.596
1999	45.501
2000	45.441
2001	45.318
2002	45.155
2003	44.995
2004	44.842
2005	44.698
2006	44.586
2007	44.476
2008	44.365
2009	44.26
2010	44.172
2011	44.188
2012	44.098
2013	44.022
2014	43.957
2015	43.906
2016	43.892
2017	43.798
2018	43.703
2019	43.609
2020	43.515
2021	43.42
2022	43.326
2023	43.232
2024	43.137
2025	43.043
2026	42.949
2027	42.855
2028	42.76
2029	42.666
2030	42.572