Year	Percent
1990	14.785
1991	14.851
1992	14.909
1993	14.917
1994	14.912
1995	14.966
1996	14.804
1997	14.662
1998	14.574
1999	14.532
2000	14.509
2001	14.816
2002	15.177
2003	15.533
2004	15.847
2005	16.111
2006	15.655
2007	15.221
2008	14.877
2009	14.694
2010	14.709
2011	15.258
2012	15.992
2013	16.859
2014	17.786
2015	18.717
2016	19.419
2017	19.473
2018	19.525
2019	19.574
2020	19.62
2021	19.665
2022	19.708
2023	19.746
2024	19.78
2025	19.81
2026	19.839
2027	19.864
2028	19.885
2029	19.902
2030	19.916