Year	Percent
1990	85.272
1991	85.469
1992	85.461
1993	85.396
1994	85.099
1995	84.754
1996	84.35
1997	83.844
1998	83.195
1999	82.422
2000	81.46
2001	80.51
2002	79.395
2003	78.202
2004	76.894
2005	75.687
2006	74.9
2007	74.105
2008	73.535
2009	73.176
2010	72.805
2011	72.472
2012	72.213
2013	71.985
2014	71.763
2015	71.573
2016	71.287
2017	71.445
2018	71.569
2019	71.669
2020	71.748
2021	71.796
2022	71.827
2023	71.832
2024	71.806
2025	71.745
2026	71.65
2027	71.531
2028	71.391
2029	71.239
2030	71.077