Year	Percent
1990	54.372
1991	54.715
1992	54.508
1993	54.414
1994	54.526
1995	54.238
1996	54.076
1997	53.68
1998	53.328
1999	52.923
2000	52.21
2001	51.835
2002	51.442
2003	51.066
2004	50.736
2005	50.436
2006	50.242
2007	50.158
2008	50.132
2009	50.09
2010	50.072
2011	50.108
2012	50.146
2013	50.174
2014	50.247
2015	50.342
2016	50.41
2017	50.506
2018	50.596
2019	50.676
2020	50.744
2021	50.783
2022	50.813
2023	50.834
2024	50.847
2025	50.852
2026	50.831
2027	50.807
2028	50.785
2029	50.773
2030	50.776