Year	Percent
1991	90.726
1992	90.291
1993	89.041
1994	87.736
1995	85.987
1996	82.308
1997	81.707
1998	80.715
1999	79.866
2000	78.787
2001	73.876
2002	67.109
2003	58.795
2004	64.174
2005	68.213
2006	68.194
2007	68.348
2008	67.823
2009	66.95
2010	65.526
2011	63.726
2012	59.518
2013	53.444
2014	59.444
2015	63.446
2016	62.134
2017	60.458
2018	59.203
2019	58.156
2020	57.176
2021	56.151
2022	55.498