Year	Percent
1990	49.129
1991	49.077
1992	49.032
1993	48.995
1994	48.98
1995	49.035
1996	49.061
1997	49.064
1998	49.087
1999	49.062
2000	49.049
2001	49.055
2002	49.064
2003	49.071
2004	49.071
2005	49.064
2006	49.068
2007	49.069
2008	49.063
2009	49.049
2010	49.028
2011	49.007
2012	48.986
2013	48.97
2014	48.968
2015	48.987
2016	49.027
2017	49.098
2018	49.183
2019	49.276
2020	49.378
2021	49.489
2022	49.607
2023	49.728
2024	49.847
2025	49.959
2026	50.067
2027	50.169
2028	50.266
2029	50.359
2030	50.451