Year	Percent
1991	48.501
1992	47.217
1993	47.266
1994	46.772
1995	47.039
1996	47.203
1997	46.995
1998	46.766
1999	46.532
2000	46.552
2001	46.35
2002	46.107
2003	45.84
2004	45.599
2005	45.282
2006	44.825
2007	44.553
2008	44.3
2009	44.137
2010	43.824
2011	43.175
2012	42.986
2013	42.763
2014	42.901
2015	42.235
2016	41.612
2017	41.492
2018	41.371
2019	41.251
2020	41.135
2021	41.025
2022	40.919