Year	Percent
1990	84.907
1991	85.615
1992	86.294
1993	86.946
1994	87.57
1995	85.743
1996	83.638
1997	81.232
1998	78.499
1999	78.137
2000	77.773
2001	77.411
2002	77.052
2003	76.698
2004	75.944
2005	76.192
2006	76.572
2007	76.869
2008	77.092
2009	77.238
2010	77.52
2011	77.838
2012	78.144
2013	78.505
2014	78.834
2015	79.1
2016	79.364
2017	79.485
2018	79.61
2019	79.738
2020	79.868
2021	80
2022	80.134
2023	80.271
2024	80.418
2025	80.576
2026	80.747
2027	80.93
2028	81.121
2029	81.31
2030	81.486