Year	Percent
1990	67.343
1991	67.441
1992	67.562
1993	67.687
1994	67.778
1995	67.819
1996	67.864
1997	67.871
1998	67.874
1999	67.914
2000	67.981
2001	68.136
2002	68.341
2003	68.551
2004	68.724
2005	69.089
2006	69.044
2007	68.933
2008	68.786
2009	68.681
2010	68.545
2011	68.4
2012	68.204
2013	67.963
2014	67.74
2015	67.911
2016	68.69
2017	68.846
2018	69.061
2019	69.262
2020	69.402
2021	69.5
2022	69.534
2023	69.526
2024	69.524
2025	69.555
2026	69.625
2027	69.72
2028	69.813
2029	69.859
2030	69.83
