Year	Percent
1990	70.62
1991	70.646
1992	68.481
1993	68.091
1994	68.46
1995	68.25
1996	68.467
1997	68.542
1998	69.809
1999	70.763
2000	71.418
2001	71.321
2002	70.895
2003	70.912
2004	71.505
2005	72.807
2006	73.459
2007	73.544
2008	72.843
2009	70.714
2010	69.198
2011	68.361
2012	68.048
2013	68.213
2014	68.087
2015	68.113
2016	67.785
2017	67.254
2018	66.715
2019	66.173
2020	65.632
2021	65.103
2022	64.59
2023	64.1
2024	63.635
2025	63.198
2026	62.783
2027	62.4
2028	62.051
2029	61.739
2030	61.462