Year	Percent
1991	67.221
1992	67.081
1993	66.969
1994	66.91
1995	66.802
1996	66.87
1997	66.902
1998	66.935
1999	66.918
2000	66.869
2001	67.451
2002	67.897
2003	68.279
2004	69.466
2005	70.682
2006	71.443
2007	72.144
2008	72.791
2009	73.508
2010	74.053
2011	75.182
2012	76.288
2013	74.791
2014	73.275
2015	71.338
2016	70.907
2017	71.29
2018	71.676
2019	72.051
2020	72.34
2021	72.619
2022	72.884