Year	Percent
1990	43.135
1991	43.501
1992	44.584
1993	45.689
1994	46.824
1995	50.083
1996	52.778
1997	55.532
1998	55.909
1999	58.153
2000	54.987
2001	60.205
2002	61.896
2003	63.549
2004	65.163
2005	66.738
2006	68.314
2007	69.843
2008	70.11
2009	70.509
2010	72.034
2011	71.303
2012	71.142
2013	70.634
2014	69.643
2015	68.067
2016	68.513
2017	68.989
2018	69.447
2019	69.892
2020	70.325
2021	70.752
2022	71.17
2023	71.577
2024	71.973
2025	72.355
2026	72.733
2027	73.103
2028	73.464
2029	73.819
2030	74.172