Year	Percent
1990	82.401
1991	81.704
1992	81.305
1993	80.942
1994	80.707
1995	80.541
1996	80.404
1997	80.324
1998	81.358
1999	82.106
2000	82.627
2001	82.983
2002	83.207
2003	83.327
2004	83.148
2005	82.853
2006	82.44
2007	81.858
2008	81.082
2009	80.085
2010	78.837
2011	77.311
2012	75.482
2013	75.296
2014	75.053
2015	74.768
2016	74.549
2017	74.593
2018	74.639
2019	74.689
2020	74.745
2021	74.807
2022	74.871
2023	74.938
2024	75.006
2025	75.075
2026	75.147
2027	75.218
2028	75.289
2029	75.36
2030	75.429