Year	Percent
1991	29.7837
1992	32.97755
1993	35.99106
1994	39.0402
1995	40.32597
1996	37.96
1997	40.8711
1998	41.9814
1999	44.01229
2000	45.20494
2001	44.4268
2002	37.70683
2003	37.68447
2004	32.57204
2005	32.29044
2006	30.60401
2007	29.52962
2008	28.70427
2009	29.09157
2010	31.01147
2011	29.25487
2012	29.7122
2013	29.25153
2014	28.34833
2015	25.58567
2016	23.10308
2017	22.77681
2018	22.30659
2019	21.24109