Year	Percent
1990	53.971
1991	54.2
1992	56.527
1993	55.129
1994	56.103
1995	58.209
1996	67.084
1997	67.313
1998	67.589
1999	68.592
2000	69.569
2001	71.104
2002	71.24
2003	70.326
2004	71.845
2005	74.296
2006	76.822
2007	80.352
2008	81.755
2009	82.493
2010	82.171
2011	83.849
2012	84.068
2013	84.579
2014	85.474
2015	85.108
2016	84.728
2017	85.129
2018	85.548
2019	85.962
2020	86.358
2021	86.732
2022	87.08
2023	87.415
2024	87.758
2025	88.121
2026	88.492
2027	88.881
2028	89.261
2029	89.593
2030	89.859