Year	Percent
1990	70.91
1991	70.902
1992	70.842
1993	70.836
1994	70.673
1995	70.621
1996	70.65
1997	70.648
1998	70.601
1999	70.593
2000	70.57
2001	70.686
2002	70.771
2003	70.861
2004	70.938
2005	71
2006	68.569
2007	66.032
2008	63.399
2009	60.684
2010	57.901
2011	55.067
2012	52.2
2013	52.112
2014	52.011
2015	51.889
2016	51.783
2017	51.511
2018	51.239
2019	50.967
2020	50.695
2021	50.424
2022	50.152
2023	49.88
2024	49.608
2025	49.336
2026	49.064
2027	48.792
2028	48.52
2029	48.248
2030	47.976