Year	Percent
1990	36.523
1991	36.369
1992	35.612
1993	34.873
1994	34.288
1995	33.831
1996	34.215
1997	35.133
1998	36.069
1999	37.243
2000	38.563
2001	39.623
2002	40.708
2003	41.817
2004	42.946
2005	44.091
2006	45.26
2007	45.706
2008	46.158
2009	46.61
2010	47.061
2011	47.524
2012	47.988
2013	48.449
2014	48.896
2015	49.487
2016	50.05
2017	50.32
2018	50.568
2019	50.795
2020	50.999
2021	51.188
2022	51.359
2023	51.514
2024	51.658
2025	51.795
2026	51.932
2027	52.066
2028	52.194
2029	52.313
2030	52.419