Year	Percent
1990	61.789
1991	61.92
1992	62.032
1993	62.16
1994	62.13
1995	62.118
1996	62.101
1997	62.036
1998	61.91
1999	61.859
2000	61.738
2001	61.629
2002	61.485
2003	61.366
2004	61.205
2005	61.009
2006	60.805
2007	60.552
2008	60.359
2009	60.285
2010	60.155
2011	60.033
2012	59.963
2013	59.928
2014	59.882
2015	59.818
2016	59.769
2017	59.719
2018	59.668
2019	59.624
2020	59.596
2021	59.583
2022	59.581
2023	59.592
2024	59.614
2025	59.648
2026	59.697
2027	59.757
2028	59.822
2029	59.882
2030	59.932