Year	Percent
1990	38.581
1991	38.5
1992	37.3
1993	36.115
1994	34.946
1995	33.796
1996	32.664
1997	31.552
1998	30.461
1999	29.392
2000	28.344
2001	27.32
2002	27.365
2003	27.188
2004	26.864
2005	26.957
2006	26.649
2007	26.727
2008	26.605
2009	26.689
2010	26.828
2011	26.866
2012	26.977
2013	27.011
2014	27.025
2015	26.949
2016	26.933
2017	26.844
2018	26.755
2019	26.665
2020	26.576
2021	26.487
2022	26.398
2023	26.309
2024	26.219
2025	26.13
2026	26.041
2027	25.952
2028	25.862
2029	25.773
2030	25.684