Year	Percent
1991	71.455
1992	69.733
1993	69.11
1994	68.609
1995	67.706
1996	66.492
1997	64.692
1998	62.532
1999	60.983
2000	60.329
2001	60.122
2002	60.381
2003	59.587
2004	61.23
2005	61.343
2006	61.052
2007	61.156
2008	60.883
2009	59.673
2010	58.825
2011	57.837
2012	56.594
2013	55.442
2014	54.216
2015	51.727
2016	46.847
2017	45.176
2018	46.666
2019	47.125
2020	47.333
2021	47.44
2022	47.466