Year	Percent
1991	85.071
1992	85.295
1993	85.177
1994	80.899
1995	81.235
1996	81.544
1997	82.3
1998	82.044
1999	81.819
2000	81.549
2001	81.208
2002	81.699
2003	82.003
2004	88.991
2005	88.761
2006	88.568
2007	88.206
2008	87.876
2009	88.117
2010	88.197
2011	86.138
2012	86.072
2013	87.288
2014	87.207
2015	86.972
2016	87.049
2017	87.024
2018	86.977
2019	86.929
2020	86.881
2021	86.833
2022	86.786