Year	Percent
1990	48.831
1991	48.975
1992	49.101
1993	49.212
1994	49.319
1995	49.424
1996	49.565
1997	49.701
1998	49.818
1999	49.908
2000	49.969
2001	50.052
2002	50.106
2003	50.136
2004	50.25
2005	50.08
2006	49.893
2007	49.678
2008	49.459
2009	49.407
2010	49.214
2011	48.976
2012	48.704
2013	48.425
2014	48.204
2015	48.061
2016	47.929
2017	47.957
2018	48.002
2019	48.024
2020	48
2021	47.957
2022	47.873
2023	47.76
2024	47.641
2025	47.529
2026	47.441
2027	47.357
2028	47.271
2029	47.174
2030	47.06