Year	Percent
1991	44.09557
1992	44.62253
1993	44.7537
1994	44.70331
1995	46.14207
1996	46.5327
1997	48.95236
1998	49.74172
1999	49.48677
2000	48.64286
2001	48.35268
2002	44.94759
2003	46.69569
2004	40.1665
2005	39.88609
2006	38.76475
2007	41.58012
2008	40.59002
2009	40.01376
2010	33.52735
2011	33.03236
2012	35.01955
2013	29.81671
2014	27.97519
2015	28.45321
2016	30.36024
2017	28.78254
2018	26.72238
2019	25.34294