Year	Percent
1991	76.774
1992	77.574
1993	77.454
1994	76.751
1995	76.607
1996	76.882
1997	77.478
1998	72.844
1999	73.074
2000	72.446
2001	73.353
2002	74.176
2003	75.406
2004	75.167
2005	75.206
2006	75.04
2007	74.622
2008	73.824
2009	72.953
2010	72.314
2011	72.693
2012	72.985
2013	72.89
2014	72.718
2015	73.82
2016	74.475
2017	74.759
2018	74.728
2019	74.7
2020	74.679
2021	74.662
2022	74.646