Year	Percent
1990	35.77
1991	36.51
1992	36.662
1993	38.25
1994	39.338
1995	39.937
1996	41.502
1997	42.489
1998	44.6
1999	46.535
2000	47.631
2001	48.016
2002	49.16
2003	49.64
2004	50.028
2005	52.383
2006	53.217
2007	54.424
2008	54.391
2009	53.789
2010	53.296
2011	52.992
2012	52.742
2013	53.128
2014	52.715
2015	52.627
2016	53.241
2017	52.976
2018	52.705
2019	52.429
2020	52.149
2021	51.898
2022	51.655
2023	51.425
2024	51.213
2025	51.023
2026	50.874
2027	50.752
2028	50.655
2029	50.579
2030	50.517