Year	Percent
1990	64.49
1991	65.356
1992	66.123
1993	67.109
1994	67.794
1995	66.789
1996	65.439
1997	63.802
1998	61.868
1999	61.573
2000	61.259
2001	61.121
2002	61.005
2003	60.935
2004	60.682
2005	60.978
2006	61.29
2007	61.499
2008	61.59
2009	61.524
2010	61.646
2011	61.882
2012	62.039
2013	62.273
2014	62.509
2015	62.737
2016	63.128
2017	63.553
2018	63.994
2019	64.413
2020	64.788
2021	65.189
2022	65.547
2023	65.865
2024	66.163
2025	66.452
2026	66.797
2027	67.145
2028	67.463
2029	67.701
2030	67.827