Year	Percent
1990	80.802
1991	80.728
1992	80.976
1993	81.95
1994	81.958
1995	81.124
1996	80.466
1997	80.329
1998	80.339
1999	80.346
2000	78.958
2001	79.092
2002	78.277
2003	77.566
2004	78.341
2005	77.826
2006	78.262
2007	79.133
2008	79.305
2009	78.384
2010	79.716
2011	80.113
2012	79.778
2013	79.649
2014	79.504
2015	79.724
2016	79.094
2017	79.344
2018	79.589
2019	79.82
2020	80.035
2021	80.219
2022	80.384
2023	80.537
2024	80.689
2025	80.848
2026	80.998
2027	81.152
2028	81.308
2029	81.461
2030	81.608