Year	Percent
1991	28.994
1992	28.603
1993	29.217
1994	29.083
1995	29.213
1996	29.56
1997	29.942
1998	30.161
1999	28.381
2000	29.354
2001	29.679
2002	27.848
2003	29.406
2004	34.102
2005	34.76
2006	36.081
2007	36.921
2008	39.436
2009	40.896
2010	46.938
2011	45.136
2012	43.46
2013	41.991
2014	43.084
2015	43.645
2016	43.634
2017	43.495
2018	43.556
2019	43.698
2020	44.113
2021	44.576
2022	44.985