Year	Percent
1990	68.338
1991	68.798
1992	68.157
1993	68.202
1994	67.284
1995	66.161
1996	66.07
1997	65.362
1998	65.402
1999	65.052
2000	65.968
2001	65.08
2002	65.915
2003	64.391
2004	64.322
2005	64.665
2006	64.221
2007	63.442
2008	63.359
2009	66.068
2010	65.368
2011	64.46
2012	65.174
2013	65.541
2014	66.096
2015	65.174
2016	63.686
2017	63.487
2018	63.311
2019	63.154
2020	63.009
2021	62.763
2022	62.535
2023	62.328
2024	62.137
2025	61.958
2026	61.688
2027	61.426
2028	61.183
2029	60.966
2030	60.779