Year	Percent
1991	80.152
1992	80.424
1993	79.622
1994	79.96
1995	77.641
1996	76.638
1997	75.603
1998	75.392
1999	74.846
2000	74.441
2001	74.186
2002	73.452
2003	72.665
2004	68.89
2005	62.832
2006	55.89
2007	61.506
2008	61.985
2009	60.272
2010	54.984
2011	54.372
2012	50.892
2013	49.681
2014	50.17
2015	52.485
2016	51.13
2017	51.166
2018	49.905
2019	49.014
2020	50
2021	50.419
2022	49.538