Year	Percent
1990	46.235
1991	46.116
1992	46.104
1993	46.072
1994	46.094
1995	46.069
1996	46.092
1997	46.126
1998	46.161
1999	46.239
2000	46.34
2001	46.369
2002	46.436
2003	46.529
2004	46.626
2005	46.715
2006	46.838
2007	46.976
2008	47.14
2009	47.333
2010	47.553
2011	47.836
2012	48.158
2013	48.497
2014	48.834
2015	49.148
2016	49.379
2017	49.465
2018	49.529
2019	49.599
2020	49.692
2021	49.798
2022	49.922
2023	50.051
2024	50.165
2025	50.252
2026	50.311
2027	50.349
2028	50.37
2029	50.384
2030	50.396