Year	Percent
1990	14.974
1991	15.28
1992	15.784
1993	16.25
1994	16.773
1995	17.344
1996	17.9
1997	18.371
1998	18.674
1999	18.907
2000	19.289
2001	19.632
2002	19.987
2003	20.374
2004	20.793
2005	21.205
2006	21.577
2007	21.951
2008	22.231
2009	22.49
2010	23.119
2011	23.761
2012	24.414
2013	25.08
2014	25.3
2015	26.1
2016	25.5
2017	25.693
2018	25.885
2019	26.078
2020	26.27
2021	26.463
2022	26.655
2023	26.848
2024	27.04
2025	27.233
2026	27.425
2027	27.618
2028	27.811
2029	28.003
2030	28.196