Year	Percent
1990	22.445
1991	22.571
1992	22.727
1993	22.893
1994	23.057
1995	23.218
1996	20.92
1997	18.816
1998	16.904
1999	18.369
2000	20.069
2001	19.748
2002	19.441
2003	19.146
2004	17.61
2005	16.231
2006	15.027
2007	14.193
2008	14.777
2009	13.043
2010	13.237
2011	13.06
2012	12.861
2013	12.626
2014	12.361
2015	12.073
2016	12.139
2017	11.869
2018	11.603
2019	11.342
2020	11.089
2021	11.023
2022	10.957
2023	10.885
2024	10.801
2025	10.7
2026	10.558
2027	10.41
2028	10.254
2029	10.091
2030	9.921