Year	Percent
1990	49.422
1991	49.364
1992	49.554
1993	49.54
1994	49.603
1995	49.715
1996	50.074
1997	50.852
1998	51.039
1999	51.323
2000	51.636
2001	52.064
2002	52.36
2003	52.729
2004	53.322
2005	53.802
2006	53.985
2007	54.316
2008	54.752
2009	55.122
2010	55.423
2011	55.452
2012	55.572
2013	55.68
2014	55.9
2015	56.11
2016	55.756
2017	55.665
2018	55.683
2019	55.811
2020	56.023
2021	55.895
2022	55.791
2023	55.741
2024	55.764
2025	55.867
2026	55.914
2027	55.989
2028	56.104
2029	56.262
2030	56.465