Year	Percent
1991	59.646
1992	58.876
1993	59.246
1994	59.835
1995	59.733
1996	59.348
1997	58.953
1998	59.262
1999	59.257
2000	58.563
2001	58.333
2002	58.282
2003	58.167
2004	57.503
2005	57.452
2006	56.799
2007	56.439
2008	56.089
2009	56.691
2010	56.299
2011	56.037
2012	55.837
2013	55.768
2014	55.449
2015	55.481
2016	55.551
2017	55.496
2018	55.449
2019	55.398
2020	55.343
2021	55.284
2022	55.223