Year	Percent
1990	85.441
1991	85.096
1992	85.165
1993	84.841
1994	84.626
1995	84.536
1996	83.866
1997	83.62
1998	84.708
1999	85.735
2000	86.705
2001	87.618
2002	88.477
2003	89.283
2004	88.167
2005	86.951
2006	85.63
2007	84.2
2008	82.657
2009	80.997
2010	79.218
2011	77.318
2012	75.3
2013	75.092
2014	74.849
2015	74.611
2016	74.507
2017	74.282
2018	74.057
2019	73.832
2020	73.607
2021	73.382
2022	73.157
2023	72.932
2024	72.707
2025	72.482
2026	72.257
2027	72.032
2028	71.807
2029	71.582
2030	71.357
