Year	Percent
1990	77.424
1991	77.079
1992	76.667
1993	76.173
1994	75.635
1995	75.098
1996	74.624
1997	74.315
1998	74.012
1999	73.703
2000	73.135
2001	72.517
2002	71.854
2003	71.158
2004	70.445
2005	69.716
2006	69.785
2007	69.988
2008	70.349
2009	70.547
2010	70.475
2011	70.368
2012	70.111
2013	69.718
2014	69.306
2015	68.909
2016	68.468
2017	68.469
2018	68.465
2019	68.454
2020	68.44
2021	68.423
2022	68.404
2023	68.395
2024	68.412
2025	68.463
2026	68.548
2027	68.663
2028	68.795
2029	68.926
2030	69.048