Year	Percent
1990	20.077
1991	20.425
1992	20.713
1993	20.922
1994	21.105
1995	21.344
1996	21.575
1997	22.016
1998	22.519
1999	23.014
2000	23.532
2001	23.843
2002	24.132
2003	24.438
2004	24.814
2005	25.225
2006	26.099
2007	26.909
2008	27.663
2009	28.275
2010	28.745
2011	29.143
2012	29.621
2013	29.957
2014	30.197
2015	30.423
2016	30.264
2017	30.172
2018	30.053
2019	29.929
2020	29.807
2021	29.549
2022	29.305
2023	29.081
2024	28.874
2025	28.675
2026	28.386
2027	28.112
2028	27.873
2029	27.694
2030	27.579