Year	Percent
1990	76.4
1991	76.077
1992	75.767
1993	75.46
1994	75.157
1995	74.887
1996	74.684
1997	74.522
1998	74.396
1999	74.297
2000	74.223
2001	74.197
2002	74.332
2003	74.619
2004	75.001
2005	75.391
2006	75.484
2007	75.547
2008	75.591
2009	75.626
2010	74.318
2011	72.832
2012	67.31
2013	72.822
2014	72.419
2015	74.125
2016	74.17
2017	74.275
2018	74.345
2019	74.358
2020	74.3
2021	74.17
2022	73.973
2023	73.735
2024	73.491
2025	73.258
2026	73.024
2027	72.8
2028	72.565
2029	72.291
2030	71.961