Year	Percent
1990	74.831
1991	74.753
1992	74.623
1993	74.381
1994	73.841
1995	73.578
1996	73.674
1997	73.825
1998	73.781
1999	73.794
2000	73.877
2001	73.954
2002	73.929
2003	74.092
2004	74.246
2005	76.086
2006	77.437
2007	76.979
2008	76.42
2009	75.677
2010	76.622
2011	77.062
2012	76.918
2013	76.488
2014	75.035
2015	75.564
2016	75.497
2017	75.741
2018	75.912
2019	75.968
2020	75.887
2021	75.656
2022	75.315
2023	74.884
2024	74.393
2025	73.871
2026	73.322
2027	72.755
2028	72.221
2029	71.788
2030	71.493