Year	Percent
1990	47.594
1991	47.52
1992	47.463
1993	47.426
1994	47.384
1995	47.339
1996	47.317
1997	47.287
1998	47.267
1999	47.238
2000	47.261
2001	47.259
2002	47.264
2003	47.331
2004	47.57
2005	47.766
2006	47.989
2007	48.244
2008	48.525
2009	48.826
2010	49.142
2011	49.469
2012	49.806
2013	50.145
2014	50.218
2015	50.271
2016	50.242
2017	50.342
2018	50.432
2019	50.519
2020	50.607
2021	50.693
2022	50.785
2023	50.88
2024	50.981
2025	51.089
2026	51.2
2027	51.322
2028	51.456
2029	51.608
2030	51.778