Year	Percent
1990	47.296
1991	47.252
1992	47.188
1993	47.114
1994	47.013
1995	46.888
1996	46.875
1997	46.824
1998	46.762
1999	46.678
2000	46.635
2001	46.667
2002	46.684
2003	46.748
2004	46.968
2005	47.518
2006	48.069
2007	48.62
2008	49.172
2009	49.723
2010	50.275
2011	50.827
2012	51.379
2013	51.93
2014	51.952
2015	51.917
2016	51.865
2017	52.081
2018	52.296
2019	52.512
2020	52.727
2021	52.943
2022	53.159
2023	53.374
2024	53.59
2025	53.806
2026	54.021
2027	54.237
2028	54.452
2029	54.668
2030	54.884