Year	Percent
1991	37.507
1992	35.97
1993	33.083
1994	35.588
1995	35.694
1996	36.064
1997	37.631
1998	39.086
1999	38.926
2000	37.931
2001	37.084
2002	36.327
2003	37.724
2004	38.01
2005	36.947
2006	37.328
2007	37.663
2008	36.69
2009	39.352
2010	39.958
2011	41.031
2012	37.561
2013	38.679
2014	38.562
2015	39.521
2016	39.882
2017	40.911
2018	41.702
2019	42.44
2020	43.056
2021	43.623
2022	44.165