Year	Percent
1991	55.851
1992	56.539
1993	59.836
1994	61.05
1995	62.244
1996	62.475
1997	63.544
1998	67.314
1999	67.83
2000	68.221
2001	70.952
2002	71.894
2003	72.393
2004	75.671
2005	76.564
2006	77.297
2007	78.039
2008	79.026
2009	79.53
2010	79.63
2011	79.888
2012	79.666
2013	79.074
2014	79.536
2015	79.694
2016	80.131
2017	80.365
2018	80.625
2019	80.906
2020	81.304
2021	81.744
2022	82.338