Year	Percent
1991	55.796
1992	54.394
1993	54.016
1994	55.806
1995	55.636
1996	57.131
1997	58.931
1998	61.267
1999	60.089
2000	62.841
2001	63.011
2002	63.724
2003	63.827
2004	64.727
2005	64.312
2006	64.854
2007	65.66
2008	66.379
2009	67.623
2010	68.39
2011	68.398
2012	69
2013	69.612
2014	69.538
2015	71.003
2016	72.599
2017	73.57
2018	74.191
2019	74.758
2020	75.442
2021	76.201
2022	76.772