Year	Percent
1990	67.548
1991	67.205
1992	66.126
1993	65.612
1994	65.021
1995	64.108
1996	64.229
1997	64.383
1998	64.711
1999	65.057
2000	65.713
2001	65.439
2002	66.058
2003	66.841
2004	67.17
2005	67.991
2006	68.199
2007	68.225
2008	68.337
2009	67.596
2010	67.306
2011	66.672
2012	66.154
2013	65.5
2014	64.967
2015	64.703
2016	64.229
2017	63.779
2018	63.293
2019	62.767
2020	62.199
2021	61.585
2022	60.943
2023	60.29
2024	59.649
2025	59.034
2026	58.443
2027	57.891
2028	57.366
2029	56.843
2030	56.307