Year	Percent
1990	67.698
1991	67.971
1992	68.174
1993	68.47
1994	68.107
1995	67.908
1996	67.897
1997	67.797
1998	67.472
1999	67.579
2000	67.345
2001	67.144
2002	65.756
2003	66.321
2004	66.804
2005	67.04
2006	67.239
2007	68.415
2008	69.46
2009	66.777
2010	66.425
2011	68.047
2012	68.485
2013	68.653
2014	69.972
2015	71.27
2016	71.387
2017	71.745
2018	72.096
2019	72.409
2020	72.668
2021	72.879
2022	73.046
2023	73.173
2024	73.272
2025	73.349
2026	73.406
2027	73.445
2028	73.472
2029	73.492
2030	73.509