Year	Percent
1990	44.479
1991	46.449
1992	48.422
1993	48.572
1994	48.726
1995	48.883
1996	49.024
1997	49.17
1998	49.953
1999	50.736
2000	50.575
2001	50.464
2002	50.351
2003	50.226
2004	50.088
2005	49.939
2006	50.288
2007	50.66
2008	51.048
2009	51.097
2010	51.858
2011	51.436
2012	51.009
2013	50.572
2014	50.454
2015	48.881
2016	50.762
2017	50.736
2018	50.698
2019	50.654
2020	50.606
2021	50.549
2022	50.495
2023	50.436
2024	50.366
2025	50.28
2026	50.177
2027	50.062
2028	49.942
2029	49.826
2030	49.72