Year	Percent
1991	72.799
1992	72.247
1993	71.958
1994	71.511
1995	72.299
1996	72.203
1997	71.897
1998	72.618
1999	72.952
2000	73.565
2001	73.577
2002	73.167
2003	73.494
2004	73.183
2005	72.88
2006	73.868
2007	72.063
2008	74.978
2009	75.768
2010	75.859
2011	75.204
2012	75.816
2013	76.197
2014	76.576
2015	76.879
2016	78.113
2017	78.398
2018	78.818
2019	79.291
2020	79.757
2021	80.199
2022	80.632