Year	Percent
1990	66.258
1991	66.006
1992	65.924
1993	65.914
1994	65.959
1995	66.118
1996	63.422
1997	65.396
1998	63.969
1999	63.684
2000	63.352
2001	62.031
2002	57.169
2003	56.476
2004	56.902
2005	55.041
2006	56.461
2007	55.743
2008	54.969
2009	55.059
2010	56.023
2011	55.971
2012	56.36
2013	56.298
2014	56.879
2015	56.514
2016	56.117
2017	56.048
2018	55.98
2019	55.913
2020	55.845
2021	55.793
2022	55.752
2023	55.683
2024	55.525
2025	55.242
2026	54.848
2027	54.323
2028	53.734
2029	53.185
2030	52.741