Year	Percent
1990	12.998
1991	13.047
1992	13.033
1993	13.033
1994	13.026
1995	12.999
1996	13.031
1997	13.038
1998	13.045
1999	13.043
2000	13.024
2001	13.08
2002	13.094
2003	13.126
2004	13.13
2005	14.702
2006	16.426
2007	18.31
2008	20.356
2009	22.568
2010	24.946
2011	25.55
2012	26.164
2013	26.787
2014	27.42
2015	27.432
2016	27.412
2017	27.655
2018	27.898
2019	28.142
2020	28.385
2021	28.628
2022	28.871
2023	29.115
2024	29.358
2025	29.601
2026	29.845
2027	30.088
2028	30.331
2029	30.574
2030	30.818