Year	Percent
1990	58.873
1991	59.268
1992	59.783
1993	60.363
1994	60.789
1995	61.126
1996	61.262
1997	61.294
1998	61.246
1999	61.199
2000	61.136
2001	61.077
2002	61.007
2003	60.913
2004	60.759
2005	60.544
2006	60.128
2007	59.631
2008	59.116
2009	58.628
2010	58.149
2011	57.997
2012	57.906
2013	57.851
2014	57.794
2015	57.714
2016	57.591
2017	57.448
2018	57.287
2019	57.108
2020	56.908
2021	56.67
2022	56.417
2023	56.143
2024	55.847
2025	55.522
2026	55.165
2027	54.789
2028	54.405
2029	54.035
2030	53.686