Year	Percent
1990	75.732
1991	75.782
1992	75.817
1993	75.835
1994	75.822
1995	75.796
1996	75.658
1997	75.436
1998	75.262
1999	75.059
2000	73.841
2001	75.471
2002	73.559
2003	74.518
2004	72.879
2005	72.949
2006	73.297
2007	73.729
2008	74.213
2009	74.7
2010	75.06
2011	77
2012	78.476
2013	77.833
2014	78.259
2015	78.703
2016	78.663
2017	78.811
2018	78.92
2019	78.963
2020	78.922
2021	78.756
2022	78.509
2023	78.202
2024	77.872
2025	77.549
2026	77.198
2027	76.858
2028	76.552
2029	76.312
2030	76.158