Year	Percent
1991	41.505
1992	42.155
1993	41.866
1994	44.311
1995	45.192
1996	45.416
1997	44.953
1998	41.068
1999	39.447
2000	45.393
2001	45.683
2002	46.431
2003	43.928
2004	42.623
2005	45.612
2006	42.429
2007	43.512
2008	40.618
2009	45.16
2010	41.708
2011	41.695
2012	41.781
2013	41.929
2014	39.587
2015	40.508
2016	40.02
2017	40.055
2018	39.9
2019	39.781
2020	39.654
2021	39.532
2022	39.412