Year	Percent
1991	80.772
1992	80.292
1993	80.081
1994	79.826
1995	79.802
1996	78.73
1997	79.156
1998	79.519
1999	79.019
2000	78.087
2001	78.148
2002	77.92
2003	77.889
2004	77.069
2005	77.306
2006	77.131
2007	77.371
2008	76.903
2009	76.917
2010	76.507
2011	76.28
2012	76.235
2013	75.992
2014	75.718
2015	76.083
2016	76.407
2017	76.401
2018	76.388
2019	76.369
2020	76.327
2021	76.283
2022	76.254