Year	Percent
1991	76.316
1992	75.641
1993	75.507
1994	74.944
1995	74.537
1996	74.01
1997	73.335
1998	72.48
1999	72.328
2000	71.348
2001	71.073
2002	70.22
2003	69.839
2004	69.245
2005	68.17
2006	67.04
2007	65.744
2008	64.959
2009	65.038
2010	64.601
2011	63.971
2012	63.582
2013	63.194
2014	63.129
2015	63.117
2016	62.249
2017	62.024
2018	61.551
2019	61.13
2020	60.62
2021	60.171
2022	59.699