Year	Percent
1991	63.959
1992	65.634
1993	70.851
1994	76.199
1995	74.259
1996	73.173
1997	74.745
1998	76.218
1999	77.644
2000	79.101
2001	80.72
2002	77.307
2003	74.312
2004	74.813
2005	74.347
2006	73.724
2007	72.522
2008	72.01
2009	69.683
2010	68.134
2011	67.577
2012	66.261
2013	66.041
2014	66.257
2015	66.662
2016	66.819
2017	66.901
2018	66.879
2019	66.846
2020	66.812
2021	66.757
2022	66.701