Year	Percent
1990	66.862
1991	66.655
1992	64.632
1993	64.153
1994	63.069
1995	62.205
1996	62.001
1997	61.76
1998	61.734
1999	61.476
2000	61.23
2001	60.952
2002	61.246
2003	61.553
2004	61.761
2005	60.97
2006	60.713
2007	60.353
2008	60.283
2009	59.45
2010	58.949
2011	58.543
2012	59.011
2013	58.307
2014	58.291
2015	58.416
2016	58.718
2017	58.34
2018	57.96
2019	57.566
2020	57.146
2021	56.697
2022	56.234
2023	55.759
2024	55.276
2025	54.788
2026	54.299
2027	53.817
2028	53.339
2029	52.86
2030	52.377