Year	Percent
1990	37.73
1991	37.67
1992	37.684
1993	37.659
1994	37.664
1995	37.214
1996	37.157
1997	36.94
1998	36.476
1999	35.963
2000	35.67
2001	35.347
2002	35.29
2003	34.829
2004	34.43
2005	34.062
2006	33.993
2007	33.769
2008	33.641
2009	33.615
2010	33.492
2011	33.57
2012	33.47
2013	33.426
2014	33.315
2015	33.038
2016	32.741
2017	32.603
2018	32.465
2019	32.328
2020	32.19
2021	32.052
2022	31.915
2023	31.777
2024	31.64
2025	31.502
2026	31.364
2027	31.227
2028	31.089
2029	30.952
2030	30.814