Year	Percent
1990	60.432
1991	60.631
1992	61.593
1993	62.318
1994	62.669
1995	62.799
1996	62.333
1997	60.007
1998	59.222
1999	58.612
2000	57.575
2001	57.781
2002	57.839
2003	59.205
2004	59.222
2005	59.282
2006	59.346
2007	59.37
2008	59.462
2009	59.523
2010	59.387
2011	59.147
2012	58.818
2013	58.361
2014	58.103
2015	57.815
2016	57.575
2017	57.505
2018	57.434
2019	57.374
2020	57.331
2021	57.299
2022	57.284
2023	57.287
2024	57.311
2025	57.356
2026	57.41
2027	57.485
2028	57.573
2029	57.667
2030	57.761