Year	Percent
1991	64.064
1992	62.338
1993	61.151
1994	60.052
1995	60.338
1996	61.724
1997	60.587
1998	59.926
1999	56.878
2000	54.653
2001	54.918
2002	55.254
2003	56.896
2004	56.407
2005	57.975
2006	59.875
2007	61.03
2008	62.486
2009	60.235
2010	58.011
2011	58.683
2012	58.972
2013	58.472
2014	59.35
2015	60.8
2016	62.06
2017	62.353
2018	62.596
2019	62.425
2020	62.187
2021	61.862
2022	61.512