Year	Percent
1990	81.783
1991	80.325
1992	79.369
1993	78.345
1994	77.233
1995	76.021
1996	74.684
1997	74.312
1998	73.994
1999	73.772
2000	73.666
2001	73.658
2002	73.706
2003	73.816
2004	74.001
2005	74.273
2006	73.241
2007	72.296
2008	70.338
2009	70.686
2010	69.953
2011	69.859
2012	69.763
2013	69.637
2014	69.448
2015	70.334
2016	71.5
2017	71.367
2018	71.131
2019	70.798
2020	70.375
2021	69.872
2022	69.285
2023	68.626
2024	67.918
2025	67.176
2026	66.425
2027	65.648
2028	64.861
2029	64.078
2030	63.311