Year	Percent
1991	60.957
1992	62.42
1993	65.198
1994	66.306
1995	67.109
1996	68.058
1997	69.009
1998	70.354
1999	71.895
2000	72.164
2001	73.211
2002	74.215
2003	75.423
2004	77.361
2005	77.527
2006	77.902
2007	78.59
2008	79.052
2009	78.663
2010	79.075
2011	79.182
2012	79.921
2013	79.048
2014	78.524
2015	78.564
2016	78.632
2017	78.808
2018	78.884
2019	78.959
2020	79.073
2021	79.238
2022	79.371