Year	Percent
1990	52.938
1991	53.474
1992	55.06
1993	55.987
1994	57.1
1995	57.587
1996	58.728
1997	58.922
1998	59.456
1999	60.069
2000	60.513
2001	60.905
2002	61.561
2003	62.659
2004	64.005
2005	65.061
2006	66.581
2007	67.755
2008	68.683
2009	69.355
2010	70.256
2011	71.232
2012	72.183
2013	73.179
2014	73.819
2015	74.708
2016	75.08
2017	75.323
2018	75.59
2019	75.868
2020	76.145
2021	76.424
2022	76.709
2023	76.985
2024	77.228
2025	77.423
2026	77.572
2027	77.673
2028	77.748
2029	77.832
2030	77.947
