Year	Percent
1990	27.38
1991	27.494
1992	27.584
1993	27.724
1994	27.547
1995	27.44
1996	27.418
1997	27.346
1998	27.169
1999	27.206
2000	27.095
2001	27.008
2002	26.875
2003	26.85
2004	26.769
2005	26.661
2006	26.568
2007	26.399
2008	26.36
2009	26.527
2010	26.482
2011	26.373
2012	26.294
2013	26.237
2014	26.154
2015	26.039
2016	25.988
2017	25.942
2018	25.896
2019	25.85
2020	25.804
2021	25.758
2022	25.712
2023	25.665
2024	25.619
2025	25.573
2026	25.527
2027	25.481
2028	25.435
2029	25.389
2030	25.342