Year	Percent
1990	50.117
1991	50.691
1992	50.798
1993	50.414
1994	50.254
1995	50.039
1996	50.085
1997	50.45
1998	50.201
1999	49.633
2000	49.28
2001	49.196
2002	48.584
2003	48.487
2004	48.3
2005	48.373
2006	48.426
2007	48.568
2008	48.588
2009	48.816
2010	48.725
2011	48.293
2012	48.286
2013	49.032
2014	49.475
2015	49.853
2016	50.6
2017	50.496
2018	50.419
2019	50.351
2020	50.278
2021	50.257
2022	50.244
2023	50.23
2024	50.202
2025	50.149
2026	50.132
2027	50.098
2028	50.041
2029	49.956
2030	49.835