Year	Percent
1990	23.487
1991	23.649
1992	23.85
1993	24.037
1994	24.217
1995	24.396
1996	21.968
1997	19.746
1998	17.726
1999	19.296
2000	21.114
2001	20.763
2002	20.424
2003	20.099
2004	18.488
2005	17.046
2006	15.796
2007	14.929
2008	15.564
2009	13.747
2010	13.956
2011	13.802
2012	13.624
2013	13.406
2014	13.161
2015	12.896
2016	12.988
2017	12.73
2018	12.478
2019	12.233
2020	11.994
2021	11.928
2022	11.863
2023	11.796
2024	11.721
2025	11.633
2026	11.507
2027	11.376
2028	11.239
2029	11.094
2030	10.942