Year	Percent
1991	38.582
1992	40.681
1993	43.283
1994	44.266
1995	44.416
1996	44.137
1997	43.412
1998	42.825
1999	41.171
2000	40.107
2001	39.767
2002	39.634
2003	39.725
2004	39.087
2005	38.576
2006	38.7
2007	40.144
2008	41.769
2009	43.196
2010	44.247
2011	43.869
2012	42.987
2013	42.61
2014	42.955
2015	42.469
2016	42.211
2017	42.379
2018	42.651
2019	42.916
2020	43.106
2021	43.22
2022	43.27