Year	Percent
1990	48.174
1991	48.211
1992	48.168
1993	47.907
1994	48.62
1995	48.453
1996	48.477
1997	48.824
1998	49.112
1999	48.939
2000	49.369
2001	48.696
2002	47.775
2003	47.976
2004	48.138
2005	48.453
2006	49.114
2007	49.411
2008	49.843
2009	49.94
2010	49.857
2011	49.732
2012	49.67
2013	49.634
2014	49.642
2015	49.301
2016	49.505
2017	49.618
2018	49.731
2019	49.844
2020	49.956
2021	50.069
2022	50.182
2023	50.295
2024	50.408
2025	50.521
2026	50.634
2027	50.747
2028	50.86
2029	50.973
2030	51.085