Year	Percent
1990	83.949
1991	84.018
1992	83.618
1993	83.37
1994	83.355
1995	83.165
1996	82.89
1997	82.56
1998	82.269
1999	81.993
2000	81.775
2001	81.767
2002	81.569
2003	81.672
2004	81.692
2005	81.327
2006	80.921
2007	80.604
2008	79.449
2009	78.251
2010	78.715
2011	79.596
2012	79.582
2013	79.524
2014	79.674
2015	79.768
2016	79.56
2017	79.456
2018	79.33
2019	79.193
2020	79.053
2021	78.932
2022	78.811
2023	78.688
2024	78.559
2025	78.424
2026	78.306
2027	78.188
2028	78.069
2029	77.949
2030	77.83