Year	Percent
1990	72.091
1991	71.674
1992	70.001
1993	68.369
1994	67.965
1995	68.506
1996	68.041
1997	67.699
1998	67.64
1999	67.315
2000	66.535
2001	66.857
2002	66.535
2003	66.484
2004	66.409
2005	67.992
2006	67.478
2007	67.699
2008	67.895
2009	67.321
2010	67.398
2011	67.36
2012	67.234
2013	67.594
2014	67.575
2015	67.306
2016	67.357
2017	67.353
2018	67.344
2019	67.322
2020	67.284
2021	67.189
2022	67.075
2023	66.952
2024	66.835
2025	66.73
2026	66.635
2027	66.562
2028	66.499
2029	66.427
2030	66.331