Year	Percent
1990	82.871
1991	83.049
1992	82.733
1993	82.244
1994	81.699
1995	81.438
1996	81.072
1997	80.925
1998	80.878
1999	80.631
2000	80.106
2001	79.671
2002	78.936
2003	78.018
2004	77.125
2005	76.392
2006	75.779
2007	75.246
2008	74.762
2009	74.306
2010	73.872
2011	73.413
2012	73.003
2013	72.625
2014	72.23
2015	71.812
2016	71.51
2017	71.596
2018	71.677
2019	71.769
2020	71.877
2021	71.992
2022	72.12
2023	72.246
2024	72.351
2025	72.424
2026	72.463
2027	72.467
2028	72.446
2029	72.413
2030	72.376