Year	Percent
1990	71.838
1991	71.706
1992	71.573
1993	71.491
1994	71.319
1995	71.133
1996	70.762
1997	70.282
1998	69.795
1999	68.304
2000	66.453
2001	65.374
2002	65.186
2003	66.438
2004	63.981
2005	62.869
2006	61.371
2007	62.092
2008	62.406
2009	62.246
2010	62.335
2011	63.623
2012	63.667
2013	64.396
2014	65.222
2015	64.993
2016	66.193
2017	66.18
2018	66.147
2019	66.062
2020	65.901
2021	65.567
2022	65.163
2023	64.703
2024	64.211
2025	63.707
2026	63.084
2027	62.449
2028	61.828
2029	61.256
2030	60.758