Year	Percent
1991	90.004
1992	90.174
1993	90.235
1994	90.347
1995	90.259
1996	91.317
1997	91.626
1998	91.565
1999	91.267
2000	91.351
2001	91.506
2002	91.496
2003	91.79
2004	91.732
2005	91.503
2006	91.512
2007	91.452
2008	91.402
2009	91.306
2010	91.255
2011	91.361
2012	91.299
2013	90.55
2014	90.385
2015	90.467
2016	90.528
2017	90.469
2018	90.477
2019	90.485
2020	90.492
2021	90.492
2022	90.493