Year	Percent
1990	81.116
1991	70.464
1992	75.346
1993	78.709
1994	80.058
1995	80.808
1996	80.551
1997	80.917
1998	81.216
1999	80.961
2000	81.131
2001	80.756
2002	80.485
2003	80.804
2004	81.112
2005	81.376
2006	81.433
2007	82.488
2008	81.769
2009	81.891
2010	81.568
2011	81.426
2012	81.23
2013	80.961
2014	80.808
2015	81.502
2016	81.58
2017	81.395
2018	81.154
2019	80.864
2020	80.54
2021	80.223
2022	79.878
2023	79.53
2024	79.221
2025	78.982
2026	78.841
2027	78.773
2028	78.745
2029	78.71
2030	78.642