Year	Percent
1990	87.335
1991	86.462
1992	85.299
1993	84.801
1994	84.538
1995	84.305
1996	84.827
1997	85.219
1998	85.526
1999	84.264
2000	82.51
2001	82.181
2002	81.614
2003	80.634
2004	79.657
2005	78.705
2006	77.97
2007	76.963
2008	76.863
2009	75.524
2010	75.62
2011	75.779
2012	75.627
2013	75.287
2014	74.746
2015	74.037
2016	73.8
2017	73.408
2018	73.011
2019	72.603
2020	72.191
2021	72.458
2022	72.755
2023	73.067
2024	73.38
2025	73.674
2026	73.797
2027	73.917
2028	74.023
2029	74.107
2030	74.164