Year	Percent
1990	81.917
1991	81.616
1992	81.459
1993	81.404
1994	81.333
1995	81.159
1996	80.85
1997	80.538
1998	80.269
1999	80.051
2000	79.862
2001	79.821
2002	79.123
2003	78.369
2004	77.519
2005	76.814
2006	76.112
2007	75.607
2008	74.664
2009	74.253
2010	74.068
2011	73.453
2012	73.544
2013	73.601
2014	73.635
2015	73.604
2016	73.213
2017	72.727
2018	72.232
2019	71.768
2020	71.356
2021	70.976
2022	70.646
2023	70.352
2024	70.074
2025	69.802
2026	69.527
2027	69.266
2028	69.015
2029	68.774
2030	68.537