Year	Percent
1990	63.424
1991	63.791
1992	63.929
1993	64.021
1994	64.429
1995	64.036
1996	63.423
1997	63.285
1998	63.619
1999	63.919
2000	63.614
2001	63.14
2002	62.7
2003	62.807
2004	62.273
2005	62.48
2006	62.39
2007	61.577
2008	61.105
2009	61.477
2010	61.473
2011	62.117
2012	63.397
2013	64.986
2014	65.605
2015	66.56
2016	67.817
2017	68.186
2018	68.51
2019	68.76
2020	68.916
2021	68.957
2022	68.876
2023	68.721
2024	68.569
2025	68.475
2026	68.418
2027	68.428
2028	68.47
2029	68.471
2030	68.387