Year	Percent
1991	68.653
1992	63.266
1993	68.66
1994	68.956
1995	78.522
1996	81.538
1997	80.793
1998	78.448
1999	78.515
2000	78.088
2001	77.779
2002	76.378
2003	77.237
2004	75.475
2005	75.136
2006	73.928
2007	72.549
2008	71.884
2009	69.24
2010	69.378
2011	72.2
2012	71.572
2013	71.711
2014	71.116
2015	69.674
2016	68.757
2017	69.289
2018	69.016
2019	68.684
2020	68.297
2021	67.907
2022	67.472