Year	Percent
1990	37.644
1991	37.511
1992	36.729
1993	35.969
1994	35.355
1995	34.867
1996	35.27
1997	36.245
1998	37.238
1999	38.487
2000	39.892
2001	41.025
2002	42.186
2003	43.374
2004	44.587
2005	45.82
2006	47.085
2007	47.648
2008	48.22
2009	48.789
2010	49.351
2011	49.916
2012	50.477
2013	51.037
2014	51.603
2015	52.289
2016	52.964
2017	53.38
2018	53.795
2019	54.201
2020	54.593
2021	54.968
2022	55.331
2023	55.683
2024	56.029
2025	56.369
2026	56.696
2027	57.021
2028	57.343
2029	57.663
2030	57.98