Year	Percent
1990	80.043
1991	80.536
1992	80.644
1993	81.191
1994	81.585
1995	81.437
1996	81.267
1997	80.633
1998	80.004
1999	79.382
2000	78.773
2001	78.199
2002	77.642
2003	77.102
2004	76.581
2005	76.079
2006	75.619
2007	75.165
2008	74.718
2009	74.289
2010	74.659
2011	74.254
2012	73.837
2013	75.193
2014	72.412
2015	72.625
2016	72.814
2017	73.007
2018	73.135
2019	73.141
2020	72.991
2021	72.708
2022	72.284
2023	71.752
2024	71.16
2025	70.545
2026	69.919
2027	69.271
2028	68.644
2029	68.091
2030	67.642