Year	Percent
1991	60.341
1992	57.81
1993	56.514
1994	60.328
1995	59.328
1996	59.621
1997	61.075
1998	61.44
1999	60.031
2000	60.115
2001	60.721
2002	60.28
2003	59.524
2004	59.607
2005	60.57
2006	62.159
2007	62.345
2008	63.567
2009	63.101
2010	61.503
2011	60.022
2012	59.634
2013	61.219
2014	61.672
2015	60.786
2016	59.825
2017	60.787
2018	60.766
2019	60.745
2020	60.728
2021	60.709
2022	60.688