Year	Percent
1991	54.84903
1992	54.70867
1993	54.75318
1994	54.64776
1995	52.49636
1996	50.31722
1997	48.0012
1998	45.56532
1999	43.26015
2000	40.84171
2001	38.42155
2002	35.95921
2003	33.48108
2004	31.02788
2005	29.89449
2006	28.81275
2007	27.71169
2008	26.52928
2009	25.29621
2010	24.11313
2011	25.86921
2012	27.01189
2013	28.0203
2014	29.24473
2015	29.47255
2016	29.26285
2017	28.90156
2018	28.3109
2019	27.57559