Year	Percent
1990	47.798
1991	47.803
1992	47.843
1993	47.85
1994	47.498
1995	47.145
1996	46.793
1997	46.442
1998	46.091
1999	45.74
2000	45.389
2001	45.039
2002	44.69
2003	44.341
2004	43.992
2005	43.645
2006	43.297
2007	42.951
2008	42.605
2009	42.26
2010	43.51
2011	45.02
2012	44.95
2013	45.55
2014	44.33
2015	44.7
2016	44.19
2017	44.19
2018	44.19
2019	44.189
2020	44.189
2021	44.189
2022	44.189
2023	44.189
2024	44.188
2025	44.188
2026	44.188
2027	44.188
2028	44.188
2029	44.188
2030	44.187