Year	Percent
1990	15.2
1991	15.024
1992	15.011
1993	15.633
1994	16.497
1995	14.176
1996	14.817
1997	15.499
1998	16.06
1999	18.073
2000	20.282
2001	19.139
2002	18.052
2003	19.019
2004	20.025
2005	21.691
2006	23.463
2007	23.806
2008	24.01
2009	25.428
2010	25.527
2011	26.062
2012	26.264
2013	26.474
2014	26.868
2015	28.144
2016	28.666
2017	28.835
2018	29.007
2019	29.181
2020	29.359
2021	29.538
2022	29.719
2023	29.902
2024	30.088
2025	30.276
2026	30.466
2027	30.658
2028	30.851
2029	31.042
2030	31.23