Year	Percent
1991	87.612
1992	87.673
1993	87.477
1994	87.227
1995	87.063
1996	87.183
1997	87.486
1998	87.653
1999	88.128
2000	88.549
2001	88.798
2002	88.576
2003	88.295
2004	88.147
2005	87.778
2006	87.687
2007	87.44
2008	88.178
2009	89.158
2010	89.893
2011	90.74
2012	90.576
2013	90.564
2014	90.464
2015	90.425
2016	90.303
2017	90.248
2018	90.202
2019	90.167
2020	90.145
2021	90.135
2022	90.137