Year	Percent
1991	60.645
1992	60.663
1993	60.469
1994	60.423
1995	60.408
1996	60.327
1997	60.279
1998	60.264
1999	60.253
2000	60.194
2001	60.125
2002	60.146
2003	60.164
2004	60.318
2005	60.449
2006	60.456
2007	60.418
2008	60.402
2009	60.388
2010	60.391
2011	60.439
2012	60.438
2013	60.46
2014	60.478
2015	60.486
2016	60.319
2017	60.249
2018	60.254
2019	60.285
2020	60.333
2021	60.388
2022	60.445