Year	Percent
1991	68.185
1992	67.517
1993	66.945
1994	66.243
1995	65.417
1996	64.57
1997	62.021
1998	62.515
1999	61.982
2000	61.399
2001	59.835
2002	60.342
2003	59.369
2004	59.682
2005	58.33
2006	57.053
2007	55.737
2008	55.293
2009	55.658
2010	53.512
2011	53.993
2012	54.006
2013	53.31
2014	53.902
2015	53.538
2016	52.152
2017	51.652
2018	50.765
2019	49.844
2020	49.036
2021	48.328
2022	47.739