Year	Percent
1990	74.262
1991	74.499
1992	74.556
1993	74.448
1994	74.202
1995	73.78
1996	73.207
1997	72.586
1998	71.892
1999	71.099
2000	70.248
2001	69.717
2002	69.18
2003	68.668
2004	68.289
2005	68.009
2006	67.437
2007	66.999
2008	66.658
2009	66.437
2010	66.305
2011	66.331
2012	66.358
2013	66.4
2014	66.52
2015	66.688
2016	66.954
2017	67.219
2018	67.447
2019	67.624
2020	67.747
2021	67.824
2022	67.844
2023	67.821
2024	67.781
2025	67.738
2026	67.698
2027	67.652
2028	67.599
2029	67.539
2030	67.473