Year	Percent
1990	27.173
1991	26.625
1992	25.409
1993	24.874
1994	24.768
1995	23.962
1996	23.405
1997	21.696
1998	20.883
1999	20.927
2000	19.595
2001	18.791
2002	19.706
2003	21.25
2004	21.648
2005	21.621
2006	20.615
2007	19.816
2008	18.268
2009	17.775
2010	18.216
2011	20.948
2012	21.247
2013	22.909
2014	24.707
2015	24.818
2016	25.598
2017	25.63
2018	25.663
2019	25.695
2020	25.728
2021	25.761
2022	25.793
2023	25.826
2024	25.858
2025	25.891
2026	25.924
2027	25.956
2028	25.989
2029	26.021
2030	26.054