Year	Percent
1990	22.503
1991	22.514
1992	22.533
1993	22.594
1994	22.665
1995	22.891
1996	23.125
1997	23.379
1998	23.387
1999	23.407
2000	23.442
2001	23.488
2002	23.551
2003	23.636
2004	23.743
2005	23.875
2006	24.408
2007	24.953
2008	25.149
2009	24.392
2010	24.464
2011	24.457
2012	25.248
2013	25.075
2014	24.873
2015	24.65
2016	24.387
2017	24.262
2018	24.112
2019	23.94
2020	23.748
2021	23.546
2022	23.327
2023	23.092
2024	22.841
2025	22.577
2026	22.315
2027	22.044
2028	21.775
2029	21.522
2030	21.295