Year	Percent
1991	74.523
1992	73.757
1993	73.386
1994	73.397
1995	72.666
1996	72.381
1997	72.785
1998	72.133
1999	72.354
2000	73.631
2001	73.401
2002	74.238
2003	75.283
2004	74.485
2005	73.328
2006	72.779
2007	72.63
2008	72.183
2009	72.277
2010	71.839
2011	71.965
2012	71.27
2013	71.242
2014	71.166
2015	70.803
2016	70.503
2017	71.353
2018	71.356
2019	70.927
2020	70.746
2021	70.56
2022	70.367