Year	Percent
1991	43.77496
1992	44.35588
1993	44.63356
1994	44.6821
1995	44.52098
1996	44.31838
1997	44.11885
1998	43.74699
1999	43.36537
2000	42.90264
2001	42.15288
2002	41.25657
2003	40.21618
2004	39.405
2005	38.5136
2006	37.44383
2007	36.51339
2008	37.77459
2009	39.44466
2010	38.58429
2011	38.92095
2012	37.2425
2013	36.26723
2014	34.81965
2015	35.32355
2016	33.59471
2017	31.33954
2018	25.67661
2019	23.94904