Year	Percent
1990	25.607
1991	25.707
1992	25.801
1993	25.843
1994	25.885
1995	25.846
1996	25.885
1997	25.949
1998	25.974
1999	25.931
2000	25.912
2001	25.859
2002	25.738
2003	25.808
2004	25.88
2005	27.592
2006	27.396
2007	25.651
2008	23.98
2009	24.079
2010	22.64
2011	24.153
2012	22.581
2013	22.966
2014	24.708
2015	24.722
2016	24.692
2017	24.461
2018	24.23
2019	23.998
2020	23.767
2021	23.536
2022	23.305
2023	23.074
2024	22.843
2025	22.612
2026	22.38
2027	22.149
2028	21.918
2029	21.687
2030	21.456