Year	Percent
1990	75.772
1991	75.58
1992	75.815
1993	74.033
1994	72.042
1995	71.389
1996	70.012
1997	68.065
1998	66.883
1999	69.737
2000	69.638
2001	68.211
2002	68.24
2003	67.769
2004	68.053
2005	68.302
2006	68.401
2007	69.48
2008	70.507
2009	70.457
2010	70.762
2011	71.141
2012	71.244
2013	71.445
2014	71.603
2015	71.933
2016	72.133
2017	71.804
2018	71.381
2019	70.923
2020	70.471
2021	69.918
2022	69.374
2023	68.852
2024	68.361
2025	67.907
2026	67.398
2027	66.938
2028	66.54
2029	66.226
2030	66.011