Year	Percent
1990	77.271
1991	77.09
1992	77.064
1993	77.14
1994	77.168
1995	76.977
1996	76.856
1997	76.765
1998	76.664
1999	76.603
2000	76.645
2001	76.586
2002	76.661
2003	76.84
2004	77.059
2005	77.268
2006	77.4
2007	77.553
2008	77.73
2009	77.958
2010	78.254
2011	78.411
2012	78.624
2013	78.881
2014	79.16
2015	79.45
2016	79.644
2017	79.783
2018	79.925
2019	80.068
2020	80.211
2021	80.356
2022	80.502
2023	80.648
2024	80.798
2025	80.951
2026	81.108
2027	81.268
2028	81.429
2029	81.588
2030	81.745