Year	Percent
1990	36.777
1991	36.85
1992	36.975
1993	37.167
1994	37.449
1995	37.16
1996	36.873
1997	36.585
1998	36.298
1999	36.014
2000	35.736
2001	36.33
2002	36.931
2003	37.538
2004	38.152
2005	38.771
2006	36.924
2007	35.128
2008	33.386
2009	31.696
2010	30.059
2011	29.164
2012	28.291
2013	28.447
2014	28.603
2015	28.745
2016	28.9
2017	28.687
2018	28.475
2019	28.261
2020	28.044
2021	27.825
2022	27.605
2023	27.383
2024	27.164
2025	26.949
2026	26.738
2027	26.531
2028	26.323
2029	26.107
2030	25.88