Year	Percent
1991	69.13
1992	69.256
1993	69.076
1994	69.05
1995	69.046
1996	69.198
1997	69.276
1998	69.514
1999	69.583
2000	69.553
2001	69.542
2002	69.374
2003	69.217
2004	68.862
2005	68.606
2006	68.436
2007	68.216
2008	68.023
2009	67.769
2010	67.393
2011	67.464
2012	67.421
2013	66.152
2014	66.239
2015	66.011
2016	66.207
2017	66.262
2018	66.342
2019	66.375
2020	66.349
2021	66.261
2022	66.355