Year	Percent
1990	80.335
1991	80.049
1992	79.953
1993	80.064
1994	80.18
1995	80.314
1996	78.177
1997	79.707
1998	78.02
1999	78.099
2000	77.508
2001	75.862
2002	72.037
2003	71.718
2004	71.975
2005	70.521
2006	72.471
2007	71.885
2008	70.608
2009	70.589
2010	72.518
2011	72.557
2012	72.91
2013	72.744
2014	73.391
2015	72.95
2016	72.293
2017	72.14
2018	71.969
2019	71.816
2020	71.699
2021	71.611
2022	71.553
2023	71.511
2024	71.464
2025	71.398
2026	71.318
2027	71.224
2028	71.123
2029	71.033
2030	70.959