Year	Percent
1990	21.481
1991	21.601
1992	21.627
1993	22.024
1994	22.378
1995	22.685
1996	22.983
1997	23.306
1998	23.662
1999	24.06
2000	23.831
2001	23.727
2002	23.584
2003	24.323
2004	25.094
2005	25.891
2006	26.642
2007	26.507
2008	26.275
2009	25.766
2010	27.105
2011	28.523
2012	28.89
2013	28.248
2014	28.462
2015	30.477
2016	30.568
2017	30.548
2018	30.53
2019	30.504
2020	30.467
2021	30.374
2022	30.269
2023	30.164
2024	30.076
2025	30.014
2026	29.95
2027	29.909
2028	29.891
2029	29.893
2030	29.914