Year	Percent
1991	76.45
1992	76.56
1993	76.711
1994	76.667
1995	76.578
1996	76.457
1997	75.214
1998	73.154
1999	75.087
2000	74.816
2001	80.192
2002	78.512
2003	76.599
2004	74.094
2005	75.514
2006	76.9
2007	78.529
2008	79.874
2009	80.878
2010	81.623
2011	81.458
2012	81.254
2013	80.928
2014	80.838
2015	80.69
2016	80.553
2017	80.778
2018	81.012
2019	81.225
2020	81.396
2021	81.53
2022	81.625