Year	Percent
1990	82.879
1991	82.8
1992	82.737
1993	82.606
1994	82.353
1995	81.958
1996	81.8
1997	81.535
1998	81.594
1999	81.266
2000	80.899
2001	80.619
2002	80.36
2003	80.065
2004	79.722
2005	79.351
2006	79.093
2007	78.822
2008	78.57
2009	78.354
2010	78.172
2011	78.124
2012	78.188
2013	78.213
2014	78.21
2015	78.165
2016	78.201
2017	78.224
2018	78.238
2019	78.235
2020	78.21
2021	78.164
2022	78.1
2023	78.021
2024	77.934
2025	77.844
2026	77.749
2027	77.651
2028	77.557
2029	77.479
2030	77.421