Year	Percent
1990	38.591
1991	38.43
1992	38.24
1993	38.165
1994	38.138
1995	38.169
1996	38.226
1997	38.342
1998	38.475
1999	38.521
2000	38.667
2001	38.854
2002	39.064
2003	39.335
2004	39.616
2005	39.945
2006	40.28
2007	40.72
2008	41.093
2009	41.515
2010	42.013
2011	42.451
2012	42.906
2013	43.393
2014	43.892
2015	44.412
2016	44.583
2017	44.928
2018	45.247
2019	45.528
2020	45.762
2021	45.95
2022	46.099
2023	46.208
2024	46.28
2025	46.318
2026	46.327
2027	46.306
2028	46.276
2029	46.261
2030	46.279