Year	Percent
1990	30.546
1991	30.5
1992	30.173
1993	29.953
1994	30.022
1995	29.619
1996	29.548
1997	29.36
1998	29.143
1999	28.999
2000	28.914
2001	28.829
2002	28.514
2003	28.137
2004	27.935
2005	27.817
2006	27.445
2007	27.328
2008	27.207
2009	27.319
2010	27.497
2011	27.52
2012	27.449
2013	27.356
2014	27.299
2015	27.222
2016	27.14
2017	27.066
2018	26.993
2019	26.92
2020	26.846
2021	26.773
2022	26.7
2023	26.626
2024	26.553
2025	26.48
2026	26.406
2027	26.333
2028	26.26
2029	26.186
2030	26.113