Year	Percent
1990	71.209
1991	70.941
1992	70.704
1993	70.716
1994	70.424
1995	70.173
1996	69.806
1997	68.6
1998	67.916
1999	67.175
2000	64.9
2001	64.345
2002	66.085
2003	64.828
2004	65.615
2005	65.624
2006	67.571
2007	69.132
2008	69.659
2009	67.116
2010	65.282
2011	65.557
2012	66.698
2013	66.242
2014	66.641
2015	67.571
2016	67.407
2017	67.252
2018	66.993
2019	66.658
2020	66.264
2021	65.731
2022	65.145
2023	64.542
2024	63.974
2025	63.478
2026	62.96
2027	62.544
2028	62.214
2029	61.945
2030	61.718