Year	Percent
1991	72.932
1992	74.126
1993	73.157
1994	74.596
1995	74.949
1996	76.225
1997	76.852
1998	77
1999	77.883
2000	78.404
2001	77.189
2002	76.927
2003	75.988
2004	75.931
2005	76.265
2006	77.64
2007	78.127
2008	78.41
2009	77.974
2010	78.041
2011	76.979
2012	76.914
2013	78.717
2014	79.32
2015	79.747
2016	80.055
2017	79.675
2018	79.957
2019	80.212
2020	80.471
2021	80.721
2022	81.044