Year	Percent
1990	82.573
1991	82.494
1992	82.441
1993	82.32
1994	82.078
1995	81.695
1996	81.522
1997	81.258
1998	81.407
1999	81.094
2000	80.735
2001	80.461
2002	80.215
2003	79.93
2004	79.593
2005	79.225
2006	78.971
2007	78.703
2008	78.452
2009	78.236
2010	78.051
2011	77.986
2012	78.055
2013	78.079
2014	78.072
2015	78.018
2016	78.04
2017	78.052
2018	78.055
2019	78.043
2020	78.012
2021	77.959
2022	77.89
2023	77.808
2024	77.719
2025	77.627
2026	77.528
2027	77.427
2028	77.331
2029	77.249
2030	77.186