Year	Percent
1990	53.805
1991	53.62
1992	53.365
1993	53.293
1994	53.304
1995	53.427
1996	53.579
1997	53.845
1998	54.149
1999	54.311
2000	54.638
2001	55.064
2002	55.51
2003	56.021
2004	56.497
2005	56.99
2006	57.543
2007	58.183
2008	58.626
2009	59.079
2010	59.598
2011	60.041
2012	60.458
2013	60.868
2014	61.252
2015	61.643
2016	61.562
2017	61.877
2018	62.194
2019	62.509
2020	62.82
2021	63.127
2022	63.43
2023	63.727
2024	64.015
2025	64.293
2026	64.562
2027	64.82
2028	65.068
2029	65.303
2030	65.525