Year	Percent
1991	56.156
1992	58.735
1993	60.723
1994	62.799
1995	64.352
1996	65.528
1997	66.707
1998	67.577
1999	67.836
2000	68.492
2001	69.174
2002	69.486
2003	69.757
2004	71.272
2005	71.784
2006	72.521
2007	73.735
2008	73.183
2009	72.266
2010	71.492
2011	71.973
2012	71.362
2013	71.9
2014	71.976
2015	72.124
2016	71.462
2017	70.762
2018	70.171
2019	69.653
2020	69.103
2021	68.534
2022	67.961