Year	Percent
1991	75.131
1992	74.789
1993	74.496
1994	74.193
1995	73.98
1996	73.779
1997	73.611
1998	73.49
1999	73.395
2000	73.12
2001	72.979
2002	73.131
2003	73.463
2004	73.399
2005	73.398
2006	73.485
2007	73.203
2008	73.217
2009	73.565
2010	72.342
2011	71.352
2012	66.026
2013	71.179
2014	70.995
2015	72.76
2016	72.789
2017	72.883
2018	72.965
2019	72.976
2020	72.889
2021	72.748
2022	72.563