Year	Percent
1990	37.036
1991	36.949
1992	36.825
1993	36.678
1994	36.528
1995	36.43
1996	36.455
1997	36.442
1998	36.43
1999	35.953
2000	35.478
2001	35.006
2002	34.538
2003	34.072
2004	33.609
2005	33.149
2006	32.693
2007	32.24
2008	31.79
2009	31.344
2010	30.9
2011	30.461
2012	30.025
2013	29.592
2014	29.164
2015	28.738
2016	28.317
2017	28.097
2018	27.877
2019	27.657
2020	27.437
2021	27.217
2022	26.998
2023	26.778
2024	26.558
2025	26.338
2026	26.118
2027	25.898
2028	25.678
2029	25.458
2030	25.238